Ok so you have a BMW 528i with the "rock solid" m52 engine. If it's so rock solid then why do they overheat and warp/ damage cyliner heads you ask? Because you don't understand how the cooling system works, you stupid american.

I think of the cooling system as a pressurized, closed circulation system. That is, the coolant is forced through the system at a greater pressure than domestic vehicles, and is contained in a sealed system.

The components:

1. radiator.

http://www.realoem.com/bmw/showparts.do?model=DD63&mospid=47585&btnr=17_0105&hg=17&fg=05

Purpose: coolant is forced through the radiator and is air cooled through the core of the radiator.

*check for: any leaks no matter how tiny, check that the front of radiator is clean from debris, remove fan shroud and check hose that is under it leading to expansion tank. Make sure drain is closed snugly.

two well known replacement brands are Behr and Nissens.

2. expansion tank:

http://www.realoem.com/bmw/showparts.do?model=DD63&mospid=47585&btnr=17_0135&hg=17&fg=05

Purpose: provides a means to top off coolant and is where the excess coolant is forced on a hot motor. You should keep this full of coolant to the "full cold/ kalt" line, top off on cool engine.

*check for any cracks or leaks, examine on warm engine- this little tank has caused alot of frustration in the past over "mystery leaks"

I am not aware of any aftermarket repalcement for this part, that doesn't mean they aren't out there.

3. mechanical fan/fan clutch:

http://www.realoem.com/bmw/showparts.do?model=DD63&mospid=47585&btnr=11_1244&hg=11&fg=35

purpose: this fan has a clutch in it that is designed to lock up as the engine gets hot, making the fan pull air through the radiator and over the engine. These clutches can go bad, I've seen an e39 540i with a seized fan clutch have the plastic fan explode and literally pound the hood with fist sized dents from the inside out.

*To test yours, start your car on cool motor. CAREFULLY take a rolled newspaper and attempt to stop the fan. It should stop no problem, if you can't stop it you need a new fan clutch, simple, huh? If you find it needs to be replaced, you'll see it can be a pain to remove. There are special tools available that hold the four bolt heads on the pulley so you can turn the fan.

My approach was to grab the pully with channel lock pliers and then turn the nut on the fan. This worked, but also broke the pulley which had to be replaced. Sooo... you either buy the special fan removal tool or run the risk of replacing the fragile pulley. BMW dealerships keep the plastic pulley in stock- imagine that.

You can get a new fan/clutch as well as the fan removal tool from any major BMW parts house like bavauto.com

4. water pump

http://www.realoem.com/bmw/showparts.do?model=DD63&mospid=47585&btnr=11_1546&hg=11&fg=35

purpose: a no brainer- the water pump is responsible for the pumping/circulation of the coolant through the components of the cooling system.

*check the pump for any play in the impeller shaft. With the belt off be sure it spins freely, there should be no bind or tough spot and it should be easy to turn. If you have tried everything and still overheating your impeller may have come off the shaft, it's happened.


5. thermostat and thermostat housing:
http://www.realoem.com/bmw/showparts.do?model=DD63&mospid=47585&btnr=11_1546&hg=11&fg=35

purpose: the thermostats on these are a lil different as well. only use OEM parts in this position. The thermostat opens and closes to keep the engine at a consistant operating temp. These don't go bad often and are generally blamed when something else is really wrong. The housing's purpose is to contain the theromstat and provide and inlet and outlet to the radiatior.

*replace the thermostat for good measure and check that the housing is properly fitted and leak free.

I have found an all aluminum thermostat housing available for the M52 through an ebay search, may be a worthwhile upgrade.

6. Coolant hoses

http://www.realoem.com/bmw/showparts.do?model=DD63&mospid=47585&btnr=11_1555&hg=11&fg=35

this chart does not apply to my vehicle, might match yours:
http://www.realoem.com/bmw/showparts.do?model=DD63&mospid=47585&btnr=11_2638&hg=11&fg=35

Got a mystery coolant leak? Maybe it's one of those hoses, huh?

*not much to say here, inspect the hoses for leaks and tears and replace as required.


7. pusher/helper fan

http://www.realoem.com/bmw/showparts.do?model=DD63&mospid=47585&btnr=64_0832&hg=64&fg=55&hl=9

Purpose: this fan has a few different speeds that are selected based on the cars needs. This fan helps cool the radiator as well as the A/C system.

*to test fan, turn on air conditioning to like 62 degrees/ climate control fan on high and make sure the snowflake button is lit up, if not push it, with the car in park. go out and look up into the grille. If it's spinning it works:) You may also test it by applying 12v directly to the control box, you are on your own there. This fan is another area that you want to keep clean and free of debris.



Now that we have examined and replaced anything faulty, let's fill it with coolant and bleed the air out of it!

here is a generic tutorial to bleed the system out , I'd appreciate it if one of our forum "experts" could elaborate- I know Jim has a trick or two that makes this easier.

http://www.bmwtips.com/tipsntricks/JC/Overheating.htm


This part is under the shroud I mentioned and connects the radiator to the expansion tank via a small diameter hose:

http://www.bmwtips.com/tipsntricks/radiator/radiator-vent-pipe.htm



If you are having troubles with overheating or 528i cooling system post it in this thread first before making a new one and I will do my best to help. From here on out if I see an 528i overheating thread that has not gone over this troubleshooting list I'm not even commenting. I think this is a solution to an ongoing problem- let's put our heads together and keep our bimmers running cool and strong!


Any other tips, tricks, sources for parts and 528i cooling system concerns are welcome!

This write-up is linked later in this thread as well, it is a very good tutorial with pictures and additional info:
http://www.bimmerboard.com/forums/posts/199986

this thread should be a sticky!

great job e39dream

Thanks alot Greg- just trying to give a little back to this community. I noticed an increase in m52 cooling problems (and alot of new 528i guys here) and just get tired of beating the same old responses into the keyboard :) At the same time though I hate to see someone post here and not get helpful info. It's a labor of love.

This is great...

Good for you E39dream. I second the sticky creation request.

I am headed to flush my cooling system tomorrow (2000 528i with 125K miles). There have been no problems to date except for squeeling when the engine is cold so I am going to have them check the belt, tensioners and idler pullies. Is there anything else which is commonly checked out??


PS this is great info and I second that it should be a stickey

Hey Karen1122- it sounds like you have a good idea what needs to be done. Be sure to replace or repack grease on any bearings on the idler pulley if the squeak persists.

Good post, thanks. :D

I have a bit of a different issue with mine. The symptoms indicate to me that the thermostat is stuck open. In colder weather the temp. gauge will not reach even halfway to what I would consider normal operating temps. Once the day warms up, it gets to the halfway point with no issues and holds there.

I had no idea that the thermostat is remotely controlled. Is it possible that this has something to do with the "electric heating element in the block?" I'd love to replace a sensor rather than pulling apart the cooling assembly.

Thanks,

Tim

thats a weird issue vacman- I looked up your symptoms in my TIS and came up with nothing. I'd post a thread about it and try to get it figured out though- that doesn't sound right at all.

Even when it's 10 degrees here like right now my car's temp needle will be exactly halfway on the guage within a 10-15 minute drive.

if the thermostat is stuck open the car will not heat up at due the engine being cooled all the time, not given a chance to warm up

I don't know if my 528i engine is an m52, but I experienced something very weird today. While sitting at a light, the temp needle slowly went to the red. After I started driving, it went back to the normal position and never happened again.
Any ideas, group? 96k on the clock.
Thanks.

hey Tom- your 1998 528i is indeed an M52 and the symptoms you describe indicate either a low coolant condition, a bad fan clutch or helper fan, possibly a combination of two of those things. This exact thing happened to me at a taco bell drive up while waiting behind the other cars, I found there to be air in the system and coolant low. A quick top off and bleed corrected the issue and it's never happened since.

Thanks e39dream, appreciate it. Just got the ride a couple months ago. Now I see from reading this thread that this is a common issue with the 528i's.

Just be aware that your cooling system needs some light maintenance once in awhile and you'll be a happy camper.

Hello there Tom, my 528 started having the same problem.the gauge needle would slowly cimb to Red/Hot while on idle and would go back to normal once i pressed the gas. Or if I had the car in parking and if i pressed the gas it would go back to normal. I first replaced the thermostat and still with the same problem. then I changed the Fan Clutch and the problem still was there. I then took my 528 to a bmw shop were the master tech said my radiator was clogged up somewhere in the bottom causing it to over heat. Im getting it back tomorrow. I cant wait, I already miss driving it .. Good luck..
I have read other threads.. where people have had the similar problem of over heating while idle and it seems like a high percent of the time it gets fixed by replacing the fan clutch..

Well Good luck again..

I also have the problem with the car never warming up, even on a 3 hour drive. The prognosis in the Mechanical Help forum was a stuck thermostat. I bought a replacement from an autoparts store, and plan on putting it in this weekend. Are there any step by step tutorials on how to do this? Given that it seems to be a common issue I think it would be a worthwhile writeup. If not I'll just wing it and try not to make "too" big of a mess :-)

Thanks Bimmerspeed, Now the dang thing is intermittently starting to overheat while driving, which I reckon is tad more serious. I was going to bleed the system and top off with coolant first and see what happens.

for the fan clutch, i thought it was the other way around? if you CAN stop the fan, then you need a new clutch. if not, then its fine.

for the fan clutch, i thought it was the other way around? if you CAN stop the fan, then you need a new clutch. if not, then its fine.

alright 328ithizz, you seem to have a hard time understanding this particular part so I'm going to take more time to explain it-as well as for future viewers.

The mechanical fan has a clutch on it. Think about the very definition of the word clutch, think about how a manual 5 speed car's clutch works. An event causes the clutch to operate, in a car's case the event is your foot releasing the pedal, in this fan clutches scenario that event is heat.

When you start your car with a cool motor (as in first time starting motor for the day) you should have no problem stopping that fan with a rolled up newspaper- if it does not stop the fan clutch has failed and is seized in a dangerous "always on" setting. It must be replaced.

The fan's clutch activates and allows the fan to be turned by the engines power only after a certain engine temperature has been reached. The fan clutch may be broken and never activate- meaning it's always "stoppable" with a newspaper no matter how hot the engine is. In this case the fan clutch should be changed as well, it's shot.

YOUR ABSOLUTE BEST BET IF YOU ARE HAVING OVERHEATING ISSUES AT STOPLIGHTS OR AT IDLE OR ANY OVERHEAT ISSUE IS TO SIMPLY CHANGE THIS PART WHEN YOU REVAMP THE REST OF THE COOLING SYSTEM.

This fan can be dangerous if it fails- is the 100 and whatever dollars a new fan clutch costs worth ruining a perfectly good hood, or worse yet taking a couple thousand dollar cylinder head with it? I didn't think so. If your 528i has over 120k miles change the damn fan clutch.

Here's a thread where the fan clutch failed:
http://forums.bimmerforums.com/forum/showthread.php?t=781493

thats a weird issue vacman- I looked up your symptoms in my TIS and came up with nothing. I'd post a thread about it and try to get it figured out though- that doesn't sound right at all.

Even when it's 10 degrees here like right now my car's temp needle will be exactly halfway on the guage within a 10-15 minute drive.


I hjad the same problem. Changed the Thermostat and it still did it until. I opened the bottom screw on the radiator and took a water hose in the fill hole, then I opened the bleed screw. With the cold water running through engine in normal running mode I heard a "Klunk sound and then the top hose and bottum hose had no hard pressure. Since then no problem. Oh I had the thermo in backwards:( :embarrasm :D

Not to seem like a dope, but is the bleed valve a long tube like device to the left of the radiator with a small cap on it?

I also have a question on the bleeder valve for a 528, because there appears to be 2. There is one on the thermostat housing, and appears to be another one on the expansion tank (doubles as the screw that locks the expansion tank in place). What one are you supposed to use when? Or is the one on the expansion tank not a bleeder valve at all, but rather simply there to lock the expansion tank in place?

I'm going out to play around with it today, maybe I'll get it figured out, but if someone could post a definate answer in this thread I'm sure it would help a lot of 528 owners.

Not to seem like a dope, but is the bleed valve a long tube like device to the left of the radiator with a small cap on it?

No, I believe that is for the AC...I'm guessing a port to recharge it. The bleed valve on the radiator is just to the right of the radiator cap (as you're facing the car.) It sits flush with the surface and has an X in it. I use a long-handled Phillips screwdriver to loosen it slowly while the car is idling.

I've been using this the last few nights after driving home to burp the system. It seems that each night it takes less time before the coolant runs clear with no bubbles, but that could just be my imagination.

I also have a question on the bleeder valve for a 528, because there appears to be 2. There is one on the thermostat housing, and appears to be another one on the expansion tank (doubles as the screw that locks the expansion tank in place). What one are you supposed to use when? Or is the one on the expansion tank not a bleeder valve at all, but rather simply there to lock the expansion tank in place?

I'm going out to play around with it today, maybe I'll get it figured out, but if someone could post a definate answer in this thread I'm sure it would help a lot of 528 owners.See above. :)

Tim

Here's a pic of the bleed screw sourced from a terrific cooling system writeup I found HERE (http://www.bimmerboard.com/forums/posts/199986).

http://www.bimmerboard.com/members/cn/E39-ReservoirClip-Removal.jpg

didn't read the entire thread and links but i'll add the following, sorry if it was mentioned already. 1) removing the fan clutch- after you've committed to doing the job, get a can of pb blaster. spray an ample amount where the nut meets the wp pulley. go about doing the preliminary work and when you get to the part where you have to remove the clutch, do this. get a long pry bar(preferably grind some material off the point of the bar so it is not as thick). standing in front of the car looking at the engine, pry bar in left hand, insert it down and catch the tip of it between one of the bolts on the wp pulley. with you right hand insert your 32mm wrench down onto the nut. put force on each and the fan should easily loosen.

2) bleeding the cooling system- the "bleeder" screw needs only to be opened one time and that is when you are refilling the cooling system to allow the air out of the system. when you are ready to refill the system, remove the screw. slowly pour coolant into the expansion tank until you start to see a bit intermittently coming out of the screw hole. pour even slower now until you see a steady stream of coolant coming out. now replace the screw and start the car. once its up to temp and cooled back down re-check the level. i've watched guys mess with that screw for 20min trying to get air out and doing nothing but making a mess.

here's a crude diagram of what i mean about the pry bar to hold the fan clutch,

2) bleeding the cooling system- the "bleeder" screw needs only to be opened one time and that is when you are refilling the cooling system to allow the air out of the system. when you are ready to refill the system, remove the screw. slowly pour coolant into the expansion tank until you start to see a bit intermittently coming out of the screw hole. pour even slower now until you see a steady stream of coolant coming out. now replace the screw and start the car. once its up to temp and cooled back down re-check the level. i've watched guys mess with that screw for 20min trying to get air out and doing nothing but making a mess.

Interesting points. I read the following from the link E39dream posted above, which is why I used the screw to bleed the system.

Over Heating Check List
by Jim Cash on 2002-11-04 I would suggest checking the coolant, and making sure it is bled properly - which can be a rather involved process to do it correctly.
The basics
Cold engine
- check that coolant level is correct
- Ignition on but engine not running
- set heter temp settings to max
- set fan manual to one of the lower speeds
- start engine and within 30 seconds rev it 3-4 times up to 3000rpm
- shut off engine before end of 30 seconds (before it starts to heat)
- reset climate to normal settings
- recheck coolant and top up if necessary.
Hot engine
- take car for a run to get up to operating temp
- using caution - slowly open the bleed valve (steam and bubbles may come out)
- close as soon as you see liquid coolant without excessive bubbles.
- do not overtighten this as they are plastic threads. Just snug till it seals fully.
- after engine cools check the coolant level again and top up if necessary.
Check coolant level every few days for a few weeks and top up again if required
- repeat the Hot engine bleed process again.
If coolant keeps droping after 2-3 top ups have the system pressure tested.
If you are still getting over temps have it analysed by a dealer. The temp is controlled by the engine computer so there may be another fault.
Cheers
Jim Cash

the m52 can take 3-4 "bleeds" before all the air has been purged from the system. The Over heating checklist is correct.

I also wanted to add that most of this info in this thread applies to any e39, except the part numbers obviously.

Here's a terrific pictorial walkthrough (http://www.bimmerboard.com/forums/posts/199986) on another board to supplement what e39dream has gone out of his way to provide on this thread already. Thanks again e39dream!

Tim

Ok, so now I am starting to overhaul my cooling system. I am taking it in stages since it is so expensive.

First I will replace the hoses and thermostat including an aluminum thermo housing and the radiator plus expansion tank.

Second I will replace the water pump, fan and fan clutch a month or so later.

My questions:

Pelican sold me SEVEN hoses to do a complete replacement. I was shocked to see that my upper radiator hose had a '96 stamp on it so it was obviously never changed. I suspect likewise for the others. How do I find where every one of these hoses goes??? Can all be accessed with relative ease?

How do I completely drain my cooling system?

I have links for the radiator, thermostat as well as system bleeding from above thread but I don't want to jump in until I have all the info in hand.

Thanks.

theres diagrams of the hoses on realoem, not the best diagrams but might help. otherwise just match the hoses one by one to the ones already on the car- shouldnt be too big of a deal.

To drain your coolant open the drain on the drivers side bottom of radiator- theres a valve.

Ok so im new to this board (daily Bimmerfest member) But lately I have had trouble with my car overheating. Ive learned alot about my engine so much that I watch the Temp needle religiously. But It all started when me and my father were leaving the BMW dealership here in Houston and we pulled out of the driveway there and got about a mile down the road and I looked over from the passenger seat and the needle was at 3/4:eek: . I was really worried, so we stopped and let it cool off. Then we make our way to Walmart and and we get on the freeway and cruise at about 60mph for 13-15 miles. We get to the parking lot and as we are looking for a parking spot it starts to climb to 3/4 again so we pull off to the side and put it in park and rev for 25-30 sec. it went down to the middle again. We were in Walmart for a good 15min or so, and we start to make our way home. The needle was steddy for the whole trip home so I thought ok just some random thing. I went on with my business of going to work a 8min drive there and back after about 5 hours there in the parking lot cooling off. I did this for about 1 week and then it started doing it again in the 8min drive(I didnt know this was possible) But it only does when Im either pulling down my street or in my driveway. Mind you it hasnt got to red yet just 3/4. So thats three times now. Now this Saturday we go to get gas and thats probably a 10 min trip one way. It did it AGAIN as we get into the driveway.:( But this time as we are sitting in the driveway idleing it actually hit RED(the red part of the little gauge lit up red). I quickly shut her down. I was frightened!! I didnt drive it for 3-4 days while Im talking my parents about how we are going to ge it to the local indy. One night my dad comes into my room and says "come here and hold this flashlight" We proceed to go outside and open the hood and look in the radiator cap, to my surprise the tank was EMPTY:eyecrazy . We were kinda eyecrazy thinking that the car should have told us that it was low on coolant. I mean it was bare dry!! The next day my dad brings home some coolant the Prestone pre mixed, and we put it in to the Cold Kault line. Now Today has been its second day of me driving it to work(8 min there and 8 min back after sitting for awhile in between). No problems yet, she warms up good to the middle and stays there. My question is do you think im ok now?? Do I need to bleed it?? Im 16 years old and I want to learn as much as I can about these cars and I think im in love!;) (with the car that is)
Help me please?!:help

hey underPAR- welcome to bimmerforums. You'll notice theres alot of 528i people here:)

if the expansion tank was bone dry you can bet your keyster theres air in the system. grab another gallon or two of the same coolant and top off/bleed the system.

"when in doubt, bleed it out." lol

hey underPAR- welcome to bimmerforums. You'll notice theres alot of 528i people here:)

if the expansion tank was bone dry you can bet your keyster theres air in the system. grab another gallon or two of the same coolant and top off/bleed the system.

"when in doubt, bleed it out." lol
Alright man thanks.
Is there a proper way to bleed it? Sorry if this was already posted.

theres a link to the bleed procedure on page 1 of this thread.

theres a link to the bleed procedure on page 1 of this thread.
thanks again, and im sorry.

hey no problem- if it wasnt there I'd have typed it out for you- I'm just lazy :)

As I posted above, I purchased an aluminum thermostat housing. I have seen some posts that seem to imply the OEM resin is better. Can I have some feedback regarding experiences with the alu vs. resin products before I put mine on the car?

Thanks!

Hey e39dream, that last post reminded me of how my issue turned out. Low coolant. I did bleed the system 2 or 3 times per instruction and topped off. Haven't had a problem since. Best 8 bucks I ever spent!

It's about time for me to do this. What kind/brand of coolant do you recommend using?

I'm just using some prestone premixed stuff I got from my local auto parts store. I had originally thought I'd go get some BMW coolant and switch to that but I've been busy and the prestone is keeping her cool.

Okay, I just got a 540i for the wife. 82K on the clock. The first thing I'd like to do is have the cooling system checked and address anything as needed.

I called a local indy shop in town and wanted to get an estimate for servvice. They only work on Europeon cars...and they specialize in BMW's.

This is the prices they gave me:

Radiator - Labor $169.20; Parts $215
Exp Tank - Labor $131.60; Parts $71.75
Water Pump - Labor $357.20; Parts $140
Thermostat - Labor $169.20; Parts $64.50
misc (coolant, extra parts..etc..) $40+

Sub Total: Labor - $827.20; Parts $491.25; Misc - $40 +
TOTAL (approx.) - $1360 + tax


I got the coolant system package price from Bill at Bimmer Clinic on here.
As a comparison this is what it would cost for parts from Bill at Bimmer Clinic: $435

Labor: Free (me :cool )


So I'm looking at right around $1400-1500 parts and labor through these folks... YIKES. :eek:

There is something to be said about rolling your sleeves up and doing it yourself. :)

I have been kicking around the idea of opening a bimmer only auto shop. hiring a certified bmw tech for major repairs and doing oil changes/ brake and cooling system jobs myself. Theres a shortage of good indy mechanics around here- I could make a fortune. I'd need someone with a big wallet to help me get started though.

On a side note....do you have after market calipers on your ride or are they just painted? They look red.

4 stock calipers painted red.

I'm just using some prestone premixed stuff I got from my local auto parts store. I had originally thought I'd go get some BMW coolant and switch to that but I've been busy and the prestone is keeping her cool.

Switch it out with either Pentosin or BMW Blue stuff. Or I can give you pointers on changing your head gasket!

SRSLY.. do it.

lol- it's on the to do list.

Put it near the top... trust me.

I cracked my radiator, or it cracked... whatever, it's cracked. On the drivers side right beneath the fitting where that hose goes. So I'm ordering a new radiator, got a decent price and all seems good.

Here's the question. Would it make sense that the radiator cracked, therefore causing the engine to overheat, or do you think the engine overheated and caused the crack?

Ben
02/2000 528iA

i know i probably did this the worng way but...

when i was filling up my resevior with coolant i left the cap open and just started the car and watched all the bubbles just come out then i put the cap on. I know the system pressurizes during driving but i figured since the car was cold the thermostat wouldnt open and everything would workout.

I cracked my radiator, or it cracked... whatever, it's cracked. On the drivers side right beneath the fitting where that hose goes. So I'm ordering a new radiator, got a decent price and all seems good.

Here's the question. Would it make sense that the radiator cracked, therefore causing the engine to overheat, or do you think the engine overheated and caused the crack?

Ben
02/2000 528iA

Ben,

It overheated because it blew out all of its' coolant. If I were you I would also buy an expansion tank, thermostat, thermostat housing (Aluminum) and a water pump while you're at it.

Use OE Coolant.. BMW or Pentosin.

what is pentosin?

I'm about to change the radiator out on my car and I need to get some fluid. I'm going to the dealership to get it, I just need to figure out how much to get. And at what mix

Similar problem to others in this thread on my 1997 528i with 120,000 miles on it. Overheats at idle when engine is at operating temperature if I'm forced to idle for 5 minutes or so. Needle moves up but if I rev the engine a couple of time it comes right back down. When moving, there is no problems. I've changed the fan clutch but that did not fix the problem. There is no evidence of coolant loss. I'm still unclear about how to properly bleed all the air out of this system. Should both bleed screws be opened at the same time? If not is there a sequence that should be followed? Should the engine be at operating temperature with engine running and radiator cap on tight? Thanks.

I do not use the bleed screw on the expansion tank, just the one on the thermostat housing.

Bleed instructions:

1. bring engine to operating temp, needle at halfway point of guage.

2. With engine idling open thermostat housing bleed screw with long screwdriver. Let all air and steam escape, tighten screw.

3. switch off motor and allow to cool to a cold engine state.

4. top off expansion tank with coolant to the full cold line.

repeat until no air comes out of the thermostat bleeder, you may have to do this 2-3 times. Some prefer to put the car on ramps to help burp the system.

http://forums.bimmerforums.com/forum/showthread.php?t=605750

fix your aux fan yourself! Thanks Pener!

Thanks for the instructions. Have followed this procedure 4 or 5 times. I get air and foamy looking coolant every time I open the bleed valve next to the thermostat. After 30 seconds or so the hissing and foamy coolant stop and nothing comes out. Should I leave it open until coolant starts to flow again or is it normal for nothing to come out once the pressure is releaved. Still am getting overheating at idle. Overflow tank is full to the cold mark when I check it.

I have changed the fan clutch and belts so that did not seem to be the problem.

Any ideas, anyone?

thanks,
Frustrated :ponder

if after releasing steam and bubbles theres no coolant flowing out the bleeder you either have too little coolant in the system or you may have a major problem such as a head gasket failure.

interesting info regarding coolant, just posting for discussion purposes.
http://forums.bimmerforums.com/forum/showpost.php?p=9304649&postcount=100

Got a question, don't wanna start a new thread if i dont have to...

My battery died out today, I had to get a jump start. While I was idling, I noticed the car was slowly overheating (according to the guage). I turned on my blower, and the temp guage went down rather quickly. My question is could there be a link between the battery dying and the car overheating? The needle has never moved past half way before until today.
Thanks, and great thread!!!

*2000 528: 86K miles....*

I am no expert but I would check to see if your belt is intact and all the things it turns are in working order under the hood- that can cause a low battery/ overheat situation if the belt is gone/ slipping badly. If the belt is still there perhaps your coolant is low or you have air in the system. wait until it's cool and open the expansion tank. is the coolant to the full cold level?

Thank you sir... will do.

I just recently went through the whole overheating deal with my 1997 528i. It would climb into the red at idle and sometimes at road speed. It would climb into the red for only around 20 to 30 seconds and then fall back to normal. I knew that I had air in the system and I bleed it 3 times with no sucess. I met a BMW mechanic that actually trained in Germany and he solved the problem for less that $1.00!! The bleeding screws have a small rubber o-ring that becomes easily damaged by the heat. My bleeding screws were not sealing and this allowed air into the system. I replaced both rubber o-rings with o-rings made of another material (polyurathane I think) and the problem disappered!!! I drove it the entire weekend in extreme heat (92F) and had absolutely no problems. I do have one question, I have only seen the electric fan come on twice since I owned the vehicle. When should it be on??????

glad to hear you got it fixed cheap! Thanks you for taking the time to share your experiences- one more thing to check :)

I have a 99 528i that I'm about to HAVE to do a cooling system overhaul. e39, you were nice enough to chime in on my post Tuesday night. I'd like to thank myself for a total lack of respect for cracks in the seprentine belts for busting, car overheating, and cracking the side of my radiator :shifty.

Question is:
In cn90's detailed writeup of Complete cooling system overhaul - http://www.bimmerboard.com/forums/posts/199986, he shows drilling a 1/16 hole in the 12 o'clock position of the new thermostat before it goes back in the housing. This will allow the system to bleed.
My parts show a complete thermostat housing with the thermostat already in place "Thermostat; Thermostat Kit with Housing and Seal". Do I need to take the thermostat out of the housing when I get it from Autohaus and drill the hole, or does this design not need the 1/16 bleed hole?

that is a great write up, thanks for posting the link for the rest of us.

As for the drilling of the thermostat I have really no idea. I personally do not drill holes in anything where there are no holes from the factory. I think my t-stat is from the factory 140k+ miles on it.

by design most thermostats have a small hole in them in the middle area. The thermostat always allows coolant to flow, it just regulates how much is flowing. If it were completely sealed when closed you'd be blowing hoses left and right. by drilling it again all I could see happening is it might take longer for the engine to reach normal temps- would a lil take longer for heat to work in the winter. I don't understand why he's drilling his thermostats- ask him to explain and let us know.

As for the drilling of the thermostat I have really no idea........... I don't understand why he's drilling his thermostats- ask him to explain and let us know.

Hello e39dream,
Here's what he wrote below. This guy has been a great source of confidence for me (from the bimmerfest forum) with his feedback this week and detailed writeup of the cooling system change.

---------------------------------------------
Here you go
If you Google "drilling hole in thermostat", you will see alot of discussion on this topic from VW, to Porsche to BMW etc. In the past, Wahler and Behr made themostat with hole pre-drilled. See the VW tstat that is pre-drilled from factory.

For some reasons unknow to human beings, Wahler and Behr stopped doing that recently.

Your 1999 528i has an electrical thermostat.

If you are skillful enough to remove the thermostat itself from the housing, then drill at 12 o'clock position. See pic.

Otherwise, you can still drill with the thermostat in place, just use a good drill bit and make sure you do not drill through the plastic housing on the other side or damage the spring.

Having a small hole prevents the phenomenon of "air lock", which is very difficult to get rid off. The hole virtually does not affect the operation of the cooling system.
When the car runs, there are hundreds of gallons of coolant/minute going through the opened thermostat anyway, so the hole has no effect during normal operation. What the hole is useful is when the car stops, air develops behind the tstat, and there is a hole to get out.

This is a trick taught to me by my cousin who has fixed bimmers for 20 years. He owns an independent shop in L.A. Mechanics have been drilling holes in thermostat for 20 years +++ (they just don't tell you...http://www.bimmerfest.com/forums/images/smilies/smile3453453.gif)

Hope this helps.
http://www.bimmerfest.com/forums/attachment.php?attachmentid=113391&stc=1&thumb=1&d=1183063091http://www.bimmerfest.com/forums/attachment.php?attachmentid=113392&stc=1&thumb=1&d=1183063091

some info on the auxilary fan:
http://forums.bimmerforums.com/forum/showthread.php?t=776768

99 528i 116K miles
Well, I've read through all these posts and I wanted to post my situation to see what I should do. On a trip home this weekend my AC was on and I saw the temp gauge in the red. I immediately pulled over and popped the hood. I checked all hoses and belts, everthing seems intacked. However, there is a plastic looking part that seems to have a phillips head scredriver part right infront of the oil filter. That was bubbling out liquid and sprayed a small amount of what I think is coolant around surronding parts. Is this a bleeder for the system? I read o-rings can go bad. I checked the fluid level, it does look low but I also don't really know what I'm looking for when it should be full. (anyone with a pic of the cap off where the level should be?) I turned the AC off and the temp returned back to normal and drove nerveously 1.5 hrs home with no more problems. I read about the fan clucth test and I was able to stop the fan pretty easily with the news paper, but I also don't know if I applied too much presure to stop it. But that appears to be OK for now.

My delima is I'm 25 and don't get paid enough to over haul the whole system even though I'm sure it could use it :) I bought the car with 80K on it and I haven't replaced anything. I'm somewhat handy but reading through these posts I'm not sure it's a job I want or can tackle. What are your thoughts on what can be fixed first to make the car driveable? What things should be replaced first and some expected costs for the dealer to fix? I don't know of any independent shops in the Madison, WI area. Thanks for the help in advance!

Andrew

That thing is the bleeder, you can get a new one at the dealer with a brand new o-ring for next to nothing, they have them in stock, or should. You probably just have air trapped in your cooling system, you can handle a top off and bleed if you read the info here. Go get a bleed screw and a gallon of coolant from bmw, put the new screw in and top off the expansion tank to the line that says full cold or full kalt. Then do the bleeding procedure. let it cool off all the way and check the level again, add fluid as needed to be in the full cold area. good luck.

Thanks! I'll pick that part up tomorrow. Questions about the system then, so since I had my AC on does that pull coolant from the rest of the system causeing it to run lower? Would that explain why if my levels were low and with the AC off there was enough in the system to keep the engine temp from jumping back up when I drove with it off?

For filling this thing i see the red floaty looking device. It doesn't push down, I would assume when in the cold position that should be suspened in the liquid and would bouce like a bobber. That picture they have on there doesn't tell me much about where to fill it it to, i just want to be sure to not over fill it. I have some Preston 50/50 mix in the basement. It says don't add water. Is that suff OK to put in?

the AC system does not use or reroute any coolant. the ac system does generate a good bit of heat under the hood when running however, shutting it off may have helped cool the motor back down. The cars heat system uses coolant, and an old trick when your car is overheating is to turn the heat on high and it will help cool the coolant cool faster.

Your expansion tank is a little different than mine, mine does not have a float, just a line that says full cold. I do know on a cold engine if it's at the correct full cold level it's just over halfway full in that expansion tank.

You need to use coolant that is approved for use in aluminum engines. read the bottle, it will say phosphate free if it is the right stuff.

hmm, well now I'm a little stuck. I tapped the float with a screwdriver, turns out it was just stuck down low. It now floats and is at the correct level so it's not low on coolant. Now what would be next on the list to check?

mechanical fan's clutch.

NEED SOME HELP!!!!!! WIFE CAME HOME LAST NIGHT AND THE CAR WAS SMOKING (white smoke)she said the gauge did not move up. i know i have a bad fan but did not have the money to fix it at the time, i had just had the ac compressor replaced when the mechanic told me my fan was bad and said not to use the ac untill i fixed it, well it's been hot here so we have been using it. anyways i put some coolant and she drove it to work today i told here not to use the ac. she called me and said when she got to work(1hr 15min drive)it was smoking again and she did not use the ac and the gauge did not go up. can someone help. i know i need to replace the fan but if the gauge didnt go up can the smoke be something else than the cooling system...

Hey Mark,

So, with my 2000 Touring, I have now experienced the VANOS issue (unresolved), the rear axle carrier bushings issue (unresolved), the A/C FSU issue (resolved), the ABS Module issue (resolved), and the broken cupholders (unresolved). You can probably see where I'm going with this...at this point, if Vegas would give me odds on when my cooling system was going to explode, I'd take "90 days" and the under. My question to you: do you think I need to overhaul the complete system, or can I just change out the points of common failure (i.e. hoses and expansion tank) and be "safe" (relative term) with that? I obviously want to do the preventive (and pre-emptive) maintenance, but I don't have a ton of cash laying around thanks to the ABS module failure, so a complete overhaul is really iffy.

What do you think?

Stephen

Honestly if cash is not too much of a concern I would do it all.

radiator/ hoses/ expansion tank/ thermostat and housing/ water pump/fan and fan clutch

I think you can get a package deal from www.oembimmerparts.com under 4 bills.

It might be better to run what you have while you recover your $ than to piece it together, especially if you are using the bmw coolant at 20 a gal.

The cooling system isn't alot of fun to work on so I suggest doing it all at once and being done with it. I know that's not what you want to hear but that's the best advice I could give.

My 528i has 143k miles now on the original thermostat, fan clutch and fan, with the hoses and expansion tank looking original as well, radiator and water pump replaced at same time, radiator was cracked in accident, water pump replaced because it was pretty hard to turn, feared a bad bearing.

Honestly if cash is not too much of a concern I would do it all.

radiator/ hoses/ expansion tank/ thermostat and housing/ water pump/fan and fan clutch

I think you can get a package deal from www.oembimmerparts.com (http://www.oembimmerparts.com) under 4 bills.

It might be better to run what you have while you recover your $ than to piece it together, especially if you are using the bmw coolant at 20 a gal.

The cooling system isn't alot of fun to work on so I suggest doing it all at once and being done with it. I know that's not what you want to hear but that's the best advice I could give.

My 528i has 143k miles now on the original thermostat, fan clutch and fan, with the hoses and expansion tank looking original as well, radiator and water pump replaced at same time, radiator was cracked in accident, water pump replaced because it was pretty hard to turn, feared a bad bearing.

OK, thanks for the input. I didn't realize the complete package was in the $400 range...should have done some more research, I just assumed it would be a lot more than that. I agree that it would be harder to piece it together, but my main concern was/is shoring up the known issues for as little cash as possible. I'm never gonna get those Beyern Mesh wheels if I keep having to spend money on ABS modules and radiators. (Kidding.)

Thanks again!

not positive on the pricing but they do offer a package deal if you contact them.

I just recently went through the whole overheating deal with my 1997 528i. It would climb into the red at idle and sometimes at road speed. It would climb into the red for only around 20 to 30 seconds and then fall back to normal. I knew that I had air in the system and I bleed it 3 times with no sucess. I met a BMW mechanic that actually trained in Germany and he solved the problem for less that $1.00!! The bleeding screws have a small rubber o-ring that becomes easily damaged by the heat. My bleeding screws were not sealing and this allowed air into the system. I replaced both rubber o-rings with o-rings made of another material (polyurathane I think) and the problem disappered!!! I drove it the entire weekend in extreme heat (92F) and had absolutely no problems. I do have one question, I have only seen the electric fan come on twice since I owned the vehicle. When should it be on??????

Are you talking about the bleeding screw on top of the expansion tank? I looked in mine today... and there was NO O-RING!!! :eek: :eek: :eek:

Any idear where one can attain one of these seemingly necessary o-rings???
:help

I just bought 2 brand spanking new bleeder screws- with o-rings for 2.95 each at Levin on wed. Tell the cashier Mark said hi and to stop being so bored! (she's fine.)

I just bought 2 brand spanking new bleeder screws- with o-rings for 2.95 each at Levin on wed. Tell the cashier Mark said hi and to stop being so bored! (she's fine.)

Haha.. she is.. I remember makin small talk with her when I got my spare key.. then she gave me the bill... :shifty

So ya just went in and asked for bleeder screws for an e39, huh?
Sounds easy enuff... even for me. :embarrasm

yup- talk to one of the guys at the parts counter thru the door right by the cashier and they'll set you up.

Thanks.... maybe I'll see about finally gettin my keys programmed too... :az

Here's a good write up a menber (CNN) asked me to post...

http://bimmerboard.com/forums/posts/199986

Probably should have put my post here... anyhow, for future researchers:
http://forums.bimmerforums.com/forum/showthread.php?t=809387

Follow-up: apparently I didn't get one of the expansion tank hoses on properly. Glad it didn't pop off during the AM commute. Fixed the "too much coolant" issue...

Ok, so I've determined I have a leak of some sort...
Saving up for parts is going to be a slow process for me right now...
Is there any long or short term danger to my enigine if I keep driving her like this? I'm not dogging her out, I'm drivin VERY conservativley i.e. speed limits, staying local and such... I check the coolant level every morning and she has not overheated on me since the first time. What do ya think???

:az

Isn't step one to pinpoint (no pun intended) the source of the leak?

Yeah... I'm off this week, so I will be able to get in there and give it a look see... as soon as the weather makes up it's fricken mind... :mad

I'm about to save up for my overhaul.... is about $400 - $500 a realistic amout to get this taken care of?

I wanna change:
Radiator
Waterpump
Hoses
Thermostat (housing)
Belts
and maybe the Fan Clutch and Thermostat if needed.

:az

I have the exactly same problem with my 97 -528. It's driving me crazy because it seems to overheat when I am running it idle. Could you be able to fix your problem? Should be nice to know...
Thanks!

I have the exactly same problem with my 97 -528. It's driving me crazy because it seems to overheat when I am running it idle. Could you be able to fix your problem? Should be nice to know...
Thanks!

I purchased a new Radiator, Thermostat, 2 Hoses, 2 Belts, and a Water Pump from Max at oembimmerparts.com for just under $400.00....

Friday is the big day.. hopefully after that, I can rest easier... cuz if I can't....

***shakes fist in air***

I purchased a new Radiator, Thermostat, 2 Hoses, 2 Belts, and a Water Pump from Max at oembimmerparts.com for just under $400.00....

Friday is the big day.. hopefully after that, I can rest easier... cuz if I can't....

***shakes fist in air***




Took us a little longer than I expected but in the end not a zip tie, piece of duct tape or hammer was used to fix your car. All OEM parts, all fitted correctly. :buttrock

Ok, ok, those o-rings weren't oem. still we did a good job.

Took us a little longer than I expected but in the end not a zip tie, piece of duct tape or hammer was used to fix your car. All OEM parts, all fitted correctly. :buttrock

Ok, ok, those o-rings weren't oem. still we did a good job.


Haha!!!
The duct tape was lookin tempting too... :stickoutt


I don't know about "we".... all I did was hold the light in the wrong places and gawk at your headlights.... :embarrasm

Hi Can Any One Help I Have A 316 Compact It Has Started To Overheat Plus There Is A Leak The Two Footwells Are Full Of Hot Water And Steam Is Comein From Behind The Heater Controls

you need a heater core would be my guess ooster- good luck- its a big job.

I've got the "other" type of tensioners, NOT the hydraulic ones. My new serpentine belt is loose no matter which way i put it on. I can't find a drawing on here for my setup.

can anybody help??? thanks, Benji

http://www.bmwtips.com/tipsntricks/Belt/belt528i.htm

WOW, that was fast, thanks.

i've got it on just like the picture in the link you posted, but it still seems loose. And i didn't need to mess with the torx, just the 16mm bolt rotated the idler so i can get the belt on/off.
I got the belts from bavauto and told them i didn't have the hydraulic tensioner so i should have the right belt. The new and old main belts seem to be the same size... simple stuff like this usually doesn't confound me so.

maybe try one more time, I know the last car I did was a 00 528i and it took me a few attempts and looking at my 98 528 to get it right.

yup, i got it on in one more attempt and then came in and saw your post. haha. it's on and now i gotta refill the coolant.

thanks, you guys make this place such a valuable resource it's insane!

haha! glad to hear you got it. I knew you would because I did the same thing and had just a bit of slack the first couple times. 3rd times a charm I always say :)

i thought the thermostat was gonna be hard once i saw i needed to take the fan off. NOT SO! It took less than a couple hours with some snack breaks and searching this site in between...

And doing the belts was even easier, i thought i'd have to figure out how much tension to put on them after installing, but the tensioners do that for you. IT's EASY. (almost) anyone can do it, seriously.

thanks dream, appreciated the help a bunch.

peace out, Benji

thanks dream, appreciated the help a bunch.

peace out, Benji

anytime Benji!

e39dream, so if my engine's getting hot at idle, bleed system first and check possible fan clutch failure? I did a complete cooling system overhaul 7 months ago (minus the fan clutch).

that sounds like a good plan of attack. bleed out air/ top up coolant and if temps continue to rise at idle check your fan clutch and aux electric fan.

that sounds like a good plan of attack. bleed out air/ top up coolant and if temps continue to rise at idle check your fan clutch and aux electric fan.

Thanks, I'll give it a shot this weekend.

hey all, im planning on doing my waterpump/themorstat hoses etc.

at oembimmer.com has a great kit, for super cheap.

http://www.oembimmerparts.com/catalog/item/4168850/4258853.htm

BMW Inspection II Kit contains the following items. Ordering Tips (http://www.oembimmerparts.com/page/page/4347898.htm)

Air Filter
Oil Filter
Cabin Air Filter (Pair)
Water pump (metal impeller)
Thermostat w/housing
Upper Radiator Hose
Lower Radiator Hose
Fuel Filter w/ Pressure Regulator or without depending on year of production.
A/C Belt
Accesory Drive Belt
Gallon of BMW Coolant (antifreeze)anyways my question is, does all the diy self info pertain to the m54 e39 530i motor as well? anything diff about doing the install opposed to the m52 528?

nearly identical process. you will have to add a radiator and expansion tank to that order and you'll replace most common points of failure.

your thermostat housing will have a wire plug coming off of it you have to unplug and your expansion tank will probably have a float type level indicator rather than a see thru tank with a full cold line. just minor differences.

thanks for the super quick reply, just got a complete diy from
Ruben at desertmotorworks.com
great guy, helped me very quickly and went out of his way for a stranger..

thanks every 1

ill post it once i convert it..if any 1 wants to see..

is this setup for the 528 cooling system same as 540 system? also if not is there a write up for the removal of the radiator on the 540i? I am trying to remove radiator but I am not sure if the fan MUST be removed or not? I'd prefer to do w/o removing fan if possilbe..
Input is appreciated.

yeah- the fan must come off. The 540 is actually easier to work on believe it or not. The Inline 6 engines are long and skinny so they take more space up front. The 540i water pump is pretty simple.

haha- it used to be. Quick links my ass.

This is great...

Good for you E39dream. I second the sticky creation request.

+100000000000000

This has been such a helpful thread. I have reviewed random threads all over the place about cooling issues, but this one put everything in one place with illustrations and links. I don't have any issues myself (yet), but this is obviously a common problem area so I was getting VERY stressed out. I'm not now that I know a lot more about it and how to handle the replacements.

Thank you very much, e39dream, and everyone else who has contributed with your problems, fixes, and suggestions.

This could help a ton of folks out there apparently. Instead of requesting that this be made a sticky, and no one has officially responded to these multiple requests a single time throughout the five pages of posts, I'd like to try a different angle: Why, oh why is this NOT a sticky? I'd like a publicly stated reason from a Forum Moderator, please. Thanks for your consideration, time, and for providing these Forums in the first place.

So far no one has posted this yet, when you overhaul ANYTHING on the cooling system, when you go to bleed it and turn on the car...turn off your ac and put it to full HEAT, so the coolant also runs though the heater core.

I've had a few trainnies' at work overheat M52 and M54s because of that(cars came back 70 miles later overheated and warpped heads/blocks).

excellent point Jack- I forgot that.

If you guys want the thread parked PM Kevlar, it's out of my hands.

PM sent.

This is a sore subject to me. If you guys want the thread parked PM Kevlar, it's out of my hands.

+1 PM sent

I also have a question on the bleeder valve for a 528, because there appears to be 2. There is one on the thermostat housing, and appears to be another one on the expansion tank (doubles as the screw that locks the expansion tank in place). What one are you supposed to use when? Or is the one on the expansion tank not a bleeder valve at all, but rather simply there to lock the expansion tank in place?

I'm going out to play around with it today, maybe I'll get it figured out, but if someone could post a definite answer in this thread I'm sure it would help a lot of 528 owners.

That answers one of my questions, now for the other:

I'm putting a *cough* Chevy V8 *cough* into an E34 and using the larger 540 E34 radiator. Since the expansion tank for that setup was not compatible with what I'm doing, I found one for a '97 or so 528 E39. I noted it has two openings on the bottom, one with barbs that look like a heater hose type connection, and another with a cap. I'm figuring that is where the coolant level sensor goes.

Looking at the diagram in the first post, the lower hose appears to go to some sort of extra pump. Since I don't have this pump, what should I do with the bottom hose connection? Can it be capped with a rubber cap? The 540 radiator has a barb fitting on it that will connect to the top fitting on the E39 tank, so that is not a problem. Is there an expansion tank for cars w/o the extra pump that does not have this fitting?

Thanks for any help.

I'd imagine you'll be fine capping it off. On some early 528i it is capped off. I have one expansion tank with a sensor there, but no wiring to connect so the sensor is a plug. :)

The extra hose goes to a small pump and some e39s have it, some dont.

Thank you for the information.

EDIT
I found info on another forum that answered this question, so I will repost it here in the event this is found in the course of a later search.

The expansion tank acts as an air removal tool in the cooling system, enhancing efficiency. For those such as myself that are using this in a non-stock setup, the lower outlet must be teed into the low pressure side of the cooling system, i.e. heater core return to water pump.

Hi everybody I am new on the forum, I bought a 1998 528i in August, it has 125k miles on it, last week all of a sudden the temp gage went to red, I stop immediately and did not use since then. I assumed that the thermostat was bad, I removed the thermostat housing and I noticed that the left side (driverside US) on the housing is very dry it seems like there were no water running in it for a while. I also noticed that the packing between the thermostat housing and the engine block is damaged, the aluminum surface on the engine is rusted. I appreciate any advice especially from E39Dream.

I removed the thermostat housing and I noticed that the left side (driverside US) on the housing is very dry it seems like there were no water running in it for a while. I also noticed that the packing between the thermostat housing and the engine block is damaged, the aluminum surface on the engine is rusted. I appreciate any advice especially from E39Dream.

http://www.realoem.com/bmw/showparts.do?model=DD63&mospid=47585&btnr=11_1546&hg=11&fg=35

replace the gasket for sure, be sure to get all of the old gasket off down to clean metal. replace your thermostat, top off system and bleed out air, see what happens. aluminum does not rust, it may be stained from a coolant leak. Let us know how it goes!

I ordered aluminum thermostat housing and thermostat at ebay for $57 the seller said the thermostat is OEM.

let us know how you like that thermostat housing, I've seen those but always been hesitant to buy one.

This thread is a great thread! Thanks for sharing. The detailed instructions on bimmerboard are great, too. I have my 98 528i cooling system dissassembled, and I'm just awaiting parts. I'm not sure which parts we're getting as I'm waiting to discuss it with my mechanic. I can't believe how easy it is to work on the cooling system and belts.

I took some pictures, but I don't have a high enough post count to post them.

Two questions:.
1) Is there a trick to getting the radiator to slide out? One mine, it catches on something on the sides.
2) A rubber grommet fell to the ground as I tried to lift the radiator out. Anyone recall a diagram pointing to where this grommet goes? I think I know where it came from, but would like to confirm it.

I did a further investigation with my cooling system today, I removed the water pump, the plastic part is all busted, I'm pretty sure this is the problem, but I might as well replace the thermostat and install an aluminum housing. What I am worrying is there might be some plastic debris from the pump into the system

if the plastic part you mention was the impeller it certainly wasn't helping. :)

Hi everyone. Does anybody know any online shop where I can buy all necessary stuff to replace cooling system in Europe?

Yes the impeller, I tape the broken impeller together and it looks like all parts are accounted for.

Yes the impeller, I tape the broken impeller together and it looks like all parts are accounted for.

you're joking. right? You can't put that thing back in there pushing hot coolant and expect tape to hold. hell- PM me your address, if times are that tough I will send you a waterpump with metal impeller free of charge. It has slight resistance while turning so I replaced it, still technically good. No warranty :)

Hi everyone. Well I've just received a new water pump, thermostat, fan clutch, upper / lower hoses and water hose outlet (my car doesn't have thermostat housing). Wish me luck.
Btw will this be enough to keep my car running without worries (at least cooling system) for more couple thousand miles? :)
Cheers

good luck with your 520i cooling system swap!

Hi everybody I received the aluminum thermostat housing but it is 3.5 inches shorter on the left than the original so I will need a longer hose. Any body has knows where to find a longer replacement hose?

car WON'T START need help!!!! I replaced the thermostat, housing, and water pump. The car did not run for a month the battery died. I owned toyota and hondas before when the battery is dead just jumper to another car and it will work. I'm not sure if BMW is the same.. I jumper with my truck but I'm not getting a continous electricity to turn the starter. I wonder if this is a BMW thing. I appreciate any advice from anybody especially from E39dream.. THANKS

car WON'T START need help!!!! I replaced the thermostat, housing, and water pump. The car did not run for a month the battery died. I owned toyota and hondas before when the battery is dead just jumper to another car and it will work. I'm not sure if BMW is the same.. I jumper with my truck but I'm not getting a continous electricity to turn the starter. I wonder if this is a BMW thing. I appreciate any advice from anybody especially from E39dream.. THANKS

jumping bimmers is bad for the electronics from what i hear so don't do it!

you can jump start it if you want, just use the terminals under the hood if possible.

I try to start jump from under the hood again. First I tried with my toyota tundra didn't work, I tried my wife's MDX, still did not work. I bought and installed a new battery from Kragen and it worked the first time I turned the ignition switch. MY ONLY WORRY IS IF I FORGOT TO TURN OFF MY HEAD LIGHT AND IT DRAIN THE BATTERY, I WON'T BE ABLE TO JUMP START THE CAR FROM ANY CAR.

you'll be ok. The car is smarter than you think, it wont let the headlights drain the battery. It may not have jump started because your old battery was really old/bad.

This is a thread for cooling systems only, if you continue to have troubles with your car starting post a new thread and we'll try to figure it out.

high newbe here having problems with 520 e39 overheating (temp gauge going red then coming back to normal )no sign of boiling engine when lift hood,no steam coolant level ok.no leaks, is temp sensor a common fault and best way to test it have tested fan clutch that seems ok too.

Hey, I've got a question regarding the interior heat. (BTW I have a '97 528i)

Well, the car overheated and well yeah, duh...low low coolant. I should have checked it before, but I didn't. Anyways, we filled it up, bleed the coolant which had a TON of air in it, and topped it off.

Well, that was a couple months ago in 60-70 degree weather. When it got cold and wanted to turn the heater on, to our surprise (pff...not really) the heat DOESN"T WORK!

The only way we can get heat into the car is if we are driving really fast...like highway/freeway speeds. Normal around town driving...forget it.

Also, NO HEAT gets to the rear passenger seats. Not too big of a deal because it's usually just me and my wife, but on the rare occassion that we do have someone...I feel bad that they are freezing.



Question...is it the coolant still? Some weird temp guage behind the center console everyone keeps talking about? Something deeper in the cooling system?

Also, when we bleed the coolant, we used the screw on the hose. (Don't ask which hose....the one with the coolant is all I know. My friend did it for me...I didn't even know you had to bleed the coolant...........uh, yeah) Should I try again and use the one on the expansion tank??


Oh...one more. That red light on the engine temp always comes on when we start the car. Maybe I never noticed it before, but does that always come on? I only noticed it after the car overheated.

THANKS!!! It's FREEZING...HELP ME!!!

high newbe here having problems with 520 e39 overheating (temp gauge going red then coming back to normal )no sign of boiling engine when lift hood,no steam coolant level ok.no leaks, is temp sensor a common fault and best way to test it have tested fan clutch that seems ok too. a high newbie? :rolleyes

sounds to me as if there is a good amount of air trapped in the system. Have you tried to bleed it?

Hey, I've got a question regarding the interior heat. (BTW I have a '97 528i)

Well, the car overheated and well yeah, duh...low low coolant. I should have checked it before, but I didn't. Anyways, we filled it up, bleed the coolant which had a TON of air in it, and topped it off.

Well, that was a couple months ago in 60-70 degree weather. When it got cold and wanted to turn the heater on, to our surprise (pff...not really) the heat DOESN"T WORK!

The only way we can get heat into the car is if we are driving really fast...like highway/freeway speeds. Normal around town driving...forget it.

Also, NO HEAT gets to the rear passenger seats. Not too big of a deal because it's usually just me and my wife, but on the rare occassion that we do have someone...I feel bad that they are freezing.



Question...is it the coolant still? Some weird temp guage behind the center console everyone keeps talking about? Something deeper in the cooling system?

Also, when we bleed the coolant, we used the screw on the hose. (Don't ask which hose....the one with the coolant is all I know. My friend did it for me...I didn't even know you had to bleed the coolant...........uh, yeah) Should I try again and use the one on the expansion tank??


Oh...one more. That red light on the engine temp always comes on when we start the car. Maybe I never noticed it before, but does that always come on? I only noticed it after the car overheated.

THANKS!!! It's FREEZING...HELP ME!!!

the bleed process may help in this case as well. The key is to set the heat at as hot as it will go and then bleed the system. If nothing else after this you can purge any additional air and you'll know right away if it fixes the problem. I know it's freezing out there to the point that frostbite is a concern. If you need help bleeding it I can walk you through on the phone. Emailed you my number.

high newbe here having problems with 520 e39 overheating (temp gauge going red then coming back to normal )no sign of boiling engine when lift hood,no steam coolant level ok.no leaks, is temp sensor a common fault and best way to test it have tested fan clutch that seems ok too.


You know I had that same problem. I know my car's not overheating, but the temp guage says it is. When I was bleeding the coolant system for the 50th time, the temp guage soared into the red zone. I read in another post that someone had the guage go to red, then when they started driving it when down, so I revved the car and it went down.

Also, when I have the air circulate the inside air, it goes to overheating, turn it off and it goes right back to normal.

the bleed process may help in this case as well. The key is to set the heat at as hot as it will go and then bleed the system. If nothing else after this you can purge any additional air and you'll know right away if it fixes the problem. I know it's freezing out there to the point that frostbite is a concern. If you need help bleeding it I can walk you through on the phone. Emailed you my number.


Hey, I emailed you back, but thought I'd put something here for everyone else's info too.


So, I've bleed the coolant a thousand times. All it's done is waste coolant and give me a huge puddle under my car. No matter how long I bleed the coolant, bubbles just keep coming out. Every once in a while though, a steady flow came out.

YES!! Or no...it didn't help the heat any. But, I just figured maybe there was more air. So, for #1001 time bleeding the coolant, I try again...and what do you know...more air and bubbles come out.

Then, nothing. No coolant, no steam, bubbles...nothing is coming out. It's like the coolant isn't moving in my car and only when I drive, does it actually circulate.


I'm not too familiar with the cooling system, but it seems like something is wrong with the circulation, rather than air bubbles. Obviously I have air, but why does the heat work when I'm driving and not when it's idling? Also, I have a small leak in the radiator...is that letting air in and if it is...the again, why does the heat only work when I'm driving??

if the coolant is not being circulated your impeller might have come off the shaft of the water pump. The pump will spin but it's not doing anything.

Might also have a clogged radiator. I once removed a rad. from a 540i that had clogged passages to the point the rad. actually distorted shape and was round on bottom :)

I'd do a cooling system overhaul, pump, hoses, rad. expansion tank, thermostat/housing, etc. good luck to you.

thanks e39dream,have put new dual temp sensor in block and bled the thing as best i could,touch wood (or my head) it seems ok plus also getting more mpg :-}

I got another question. So it seems as if the problem is worsening. Usually the heat would kick in between 2k-3k rpm. Now I have to gun it up to 5k + to get any heat out of the car.

My question is, do you think this is a clog and that only at high rpms is the cooling system pressurizing correctly and pumping the coolant around??

Or could it be a problem with the water pump like stated above? At low rpms, the pump is spinning, but not doing anything.

Again, I'm limited on knowledge of how cooling systems work, but from what I understand...the pump works at lower rpms and then sort of shuts off and lets the pressure pump at higher speeds, so that it isn't pumping so hard that it cools the car down too much. I had a Nissan before, so I know that makes a difference. We used to put electric water pumps on our cars to eliminate a pulley and decrease the resistance on the engine, therefore 'freeing up' some horsepower. But, we also had to put switches inside the car to be able to shut it off at freeway speeds because the engine would run too cool.


Thanks!

there is no provision to shut off the stock water pump. If the engine spins at 5000 rpm so does the water pump.


I suggest you order a new water pump and thermostat+ housing at very least and replace them. It sounds as if your old pump may have had the impeller come off the shaft inside there. The shaft itself or whatever is still attached to it may be circulating coolant at high rpm. Also be absolutely sure there is enough coolant in there to begin with.

good luck to you.

Thanks for all the help. I'll let everyone know what happened. I'm going to order a new radiator and water pump with some hoses. On a tight budget, so we'll see.

On a little side note. Don't know if anyone would agree with what I did, but I overfilled the coolant to where it's almost coming out. This actually helped with the heat issue for now. It still doesn't heat up all the time, but I do get heat again at lower rpms when I am driving. Don't know if that means anything, but it sure does feel good to have heat in single digit temperatures!! Thank God of heated seats!!!!!!!!

Question on the rolled up newspaper test on a cold engine. I went to try this but I didn't use the whole newspaper, just a couple of sections rolled up. Started to try to stop the fan, but imo, the thing was just going to chew up the newspaper with a few slight tests.

Are we talking using the whole newspaper to test? Maybe I was a little scarred to really push the rolled up newspaper in there. If my fan clutch is really shot and running full speed at a cold start, will I harm anything if I get kitty litter out of the newspaper?

Thanks.. just want to be careful in testing..

umm yeah- you dont want kitty litter anywhere under the hood. :) Roll up a sunday paper and stick it in there.

Just an update on my 'progress'.

Well, bleeding on just a warm engine never really helped anything. In fact, it made it worse. I contributed this to only having the amount of suggested coolant in the engine (i.e. where the line for cold level is).

So, I filled it to the top of the tank. Then it sank down a bit and I did it again. Well, that helped get some heat back into the car finally!! But still wasn't getting any while driving slower.


Well, I did something that I haven't read about and don't know if it's recommended, but whatever...it must have helped. One day after driving for a while, I came home and bleeded the system on not a warm engine...but a hot engine. Tons of steam came out for a good minute or so, car still running, heat on blast...

Then I turned the car off and let it sit. The next morning I topped off the coolant way passed the recommended line. Now, I get heat all the time. The engine has to fully warm up before I get any, but at least at stops I'm getting warmer air. Not hot, but better than luke warm and DEFINATELY better than straight outside cold air.


So, for now...I'm not replacing anything. I know I need to, but when you can't afford it, you can't afford it. I'm moving in two months and getting out of the military. So, I'm not trying to spend ANY money I don't have to. I don't know what kind of job I'm going to have, where I can afford to live...etc etc etc, so for now, a cooling system overhaul is not in the works. But, I'll be towing the Bimmer from Kansas City to Sacramento, so no worries on the long drive. Once home I'll replace the whole shebang, but for now...I'm happy with just over flowing with the coolant.







I also want to point out that I think that someone put straight coolant into the engine. The stuff was always coming out dark green. Definately lighter colored than premixed 50/50 stuff I put in. So, it may just be in my head, but maybe the coolant wasn't circulating properly and wasn't extracting the heat for the car properly as the 50/50 mix would do. But again, that's just my non-mechanic hypothesis.

hi Guys Im new here,my name is Vlad, just got myself a 2001 BMW 525i with a sport package and a 5 speed,97Kmiles. i like this car a lot, very much and enjoy it every minute i'm close to it...
it's got a radiator leak though.it's from a crack on the plastic on the side of the radiator.
it's not very big but I add coolant everyday. so i m gonna buy a new one tomorrow and some coolant too. is it difficult to change it ? my biggest concern is not to let air inside the system.
thanx in advance.

528i cooling system overpressure
I seem to have a system that is overpressure at normal operating temperature. I recently replaced the old expansion tank and cap as the old one had developed a crack at the top seam. I filled and bled the system per the Bentleys manual. After about a half hour of operating at full temperature I noticed the guage swing due to a bubble in the system. Coolant had leaked out from the cap. I suspected a bad tank or cap, so replaced them with a second set. Same result. I took it to Motorwerks BMW for a pressure check and diagnosis. They drained, refilled and bled the system and ran it with no leakage. I paid for the service and took the car. With no bubbles in the system, the guage stays centered and the heating system operates normally. Aftter about a half hour I noticed a guage swing again, indicating the same problem again. When I got home, sure enough coolant had leaked from the cap again. What could cause this overfilling of the expansion tank or overpressure of the system?

if the guage moves from center it's overheating or about to.

This sounds like it might be a bad fan clutch, or low coolant.

Do any of you have a list of the torque settings for the cooling system. What should the hose clamps be turned to on the plastic housing? What is the required torque for the Water pump, thermostat, tensioners etc?

I replaced the entire cooling system, belts, hoses, pullies, tensioners, fan, expansion tank. I put a Hepu pump in, a OEM thermostat. The result is I have water splattering over my belts and the front end of the engine compartment. It is a challenge to see where it comes from. I want to be sure I did not under torque something.

Thanks John

Replace your radiator, it is not difficult. You will have to drain your system, so you will have to bleed the air out.

I suggest, like others here will, that you replace all the stuff at the same time. Like your belts, hoses etc. For the 528i the biggest pain is getting the radiator and the shroud out. just be patient, and gentle, don't force things.

John

wow! great thread! you guys should start one about rebuilding the suspension.

cooling questions:

does Samco or anybody else make a hose kit for the 528i ?
would you recomend installing a high-performance/EMP water pump instead of OEM ? .

I am new to this and again want to say what a useful thread this is.

As with many post I believe I have air in the system and have had the fixed previously at a garage. As this costs to do each time (every couple of months) I have attempted to follow the bleeding instructions posted before.

Questions
When bleeding a hot engine how long might it take to get all the air out? I have opened the thermostat bleed valve, got a lot of steam for serveral minutes but not bubbles or fluid.

What is the likely cause of air getting in, in the first place. Other posts have suggested fault bleed screws but as these are at the top of the system surely this would have a similar effect to drilling the thermostat.

Once the overhetating problem has started sometmies the car will run for several miles at normal and the heater working. Other times it will barely go 1/2 mile before hitting red again. Could this just be a massive air lock?

Oh yes. Coolant levels are normal with no obvious leaks.

Any help or suuggestions greatfully received to avoid another trip to the garage

Further to my last post I gave this some more thought over the weekend and seem to have fixed / improved the situation

After another attempt to bleed the system nothing was coming out of the thermostat bleed valve yet the car overheated at idle in about 10mins.

Assuming an air lock was present and giving a false coolant level (which appeared normal) after cooling I tried putting an empty water bottle in the coolant filler, making the best seal I could and squeezing to blow air into the expansion tank (I know it sounds a bit counter productive). After several sqeezes, the coolant level in the resevior had fallen. So I topped up and repeated. I must have added nearly 2litres before deciding to give it a try. The heater worked strainht away and temp guage stayed in the centre despite my best efforts to get the the engine hot.

So my question is, given that coolant does not seem to be leaking onto the drive what are likely ways for that amount of air get in overy couple of months? Could it be something serious?

i would like to replace my primary mechnical fan with an electric fan on my 1998 528 m52 engine, any thoughts on where i should hook up the thermo switch to turn the fan on/off. any help would be great. thanks in advance

I have some questions regarding the 528i cooling system

If I only open the cap of the expansion tank to see the coolant level but not adding the coolant (the expansion tank is old and very difficult to see the coolant level from the outside) ...do I need to bleed the system (condition: the engine is cold and has never been use since yesterday), and if the coolant level is between cold and empty...and I add the coolant level to KAlt.....do I need to bleed the system??

thank you for your help..

I check mine in the same manner, there is no need to bleed it out every time you open the cap on the expansion tank.

The bleed procedure ensures that all air is out of the passages of the motor and the radiator/ hoses. You will always have air space in that expansion tank- that is how it is designed. When your car starts to get too hot the coolant expands and that space in the expansion tank is crucial to the system, its where the excess coolant goes instead of blowing out a hose or the radiator.

i got a bmw 97 528i model and facing problem with overheating.
I changed thermostat, water pump, fan shroud and fan clutch.
But still my problem is not solved. After driving 5km the guage goes to red and within 0.5km it is coming back to normal.

Any suggestions is much appreciated

hey Sam, it sounds like there is still air in the system and or a low coolant situation. Did you bleed the air from the system after you changed parts?

I have a question. I have been following the advise in this thread b/c of an overheating issue. I keeping checking the coolant level when my engine is cold, always needs to be topped up with like 1/2 qt. Then when it is hot I bleed it. I was wondering if low coolant is my problem, or others problem in this thread, why do we not get a low coolant warning light on the dash?