318 (M42) thermostat replacement (and coolant change) writeup.

[Zoso]

I replaced my thermostat this past weekend. The procedure was a pain in the ass, but if I had to do it again, it would take me 1/4 of the time knowing what I know now.

The procedure worked any my temp needle (which used to barey hit the 1/4 mark) now goes to about 50% and the cabin heat is awesome!

I took some pictures and added a writeup on how to replace the thermostat and change the coolant:

http://zoso.no-ip.org/318i-thermostat.html

[Snarcher!]

"mad props" for this write up, i am doing mine tonight but i have the 6 cyl, is it still the same procedure? I dont think ill have to remove the fan or anything as the housing is right up top and easy to get to.

has anyone else done a write up on the 2.5l?

[drshoebocks]

Nice write up, I have an M20, but it is always great to see someone take the time to show step by step procedures on anything e30 related. These kinds of write ups are great because unlike the bentley they also go through common problems that can occur. Great job

[Snarcher!]

at the end, when you get it all together and bleed it, does that mean you just loosen taht screw, and pour it in the resevour until it all starts bleeding out?

[Zoso]

I think the M20 is very different than the M42... but after a quick look at the ETK, it looks like it is easier to change the thermostat on the M20 than it is on the M42. Anyone with first hand experience with both?

Regarding the bleeding, check out this quote this from the pelican parts writeup. Doesn't the M20's cooling system have a seperate tank? I guess that means it is self bleeding.


Remove the small plastic bleed screw to the right of the radiator cap. On M3 engines, this screw is located on the thermostat housing. Using a large funnel in the expansion tank, slowly fill the car with new coolant. Use a 50/50 mixture of antifreeze and distilled water. Do not use tap water or spring water, as these have impurities that will contaminate your system. Distilled or ionized water is 100% H20, and does not contain any minerals, additives, or impurities. Fill the system very slowly, as it will take a bit of time for the coolant to get to all points in the system. On 4-cylinder cars, you will need about 7 quarts (6.5 liters). For the six cylinder cars, you will need 10.6 quarts (10 liters). M3 motors require 11.1 quarts (10.5 liters).

When the system is full of coolant, you will need to bleed air out of it. This applied only to the cars that have the expansion tank attached to the side of the radiator. Other BMWs with a separate, external expansion tank are self-bleeding. The procedure for bleeding these cars seems somewhat sloppy and not too slick. With the bleed screw removed, fill the expansion tank until fluid begins coming out of the bleed screw. Continue filling until there are no more bubbles coming out, as shown in Figure 13. This, of course will mean that plenty of coolant will spill all over your radiator, and down onto the ground. Have a catch pan ready to capture this coolant spill. When no more bubbles exit out of the bleed screw, tighten it to 8 Nm (71 in-lb).

Now, run the engine until it reaches it's operating temperature. Turn off the engine and let it cool down. Then, top off the coolant in the expansion tank to the appropriate level, if necessary.

[Snarcher!]

there is a bleed screw on top of the t-stat housing, and there is an expansion tank sitting on the driver wheel well between the head lights and the wheel. ill ad mit, i was staring at the radiator saying "where the hell is the cap?" lol

[Zoso]

:D

Just as an FYI that pelican parts quote is for the E36.


Did you do the thermostat already?

[Snarcher!]

40$ at the dearler WITH the BMW CCA discount!

my accord was like 16 total. to be expected i suppose.

im going to take lots of pics tonight and perhaps we can add them to your page zoso

[Zoso]

40$ at the dearler WITH the BMW CCA discount!

my accord was like 16 total. to be expected i suppose.

im going to take lots of pics tonight and perhaps we can add them to your page zoso

$40 for a new thermostat? I think I ended up paying $40 or so for 2 gallons of the blue BMW nitrite and phosphate free antifreeze. That hurt, but electrolysis should be for removal of bikini line hair, not my engine.

My writeup is pretty M42 specific. The M42 and M20 are such different beasts. The thermostat replacement procedure is different. Different radiator/expansion tank layout. I bet the block drain plug is in a different area. I'd hate to confuse people. If you want, we can use your pictures to make an M20 specific thermostat replacement procedure. I can host it.

[BrandC]

bump for a good DIY!

[Snarcher!]

just got done, 2.5l write up to follow!

[Zoso]

just got done, 2.5l write up to follow!

Start a new thread about it. If all goes well, it'll take 1 year for someone to respond :D

[Grant01]

why does bmw make what should be a super easy job, a pain in the ass?

[Snarcher!]

not a pain in the ass at all,

here is my write up

http://numassmontring.com/t-stat.htm

[Antrieb]

LOL great writeup snarcher!

http://numassmontring.com/photogallery/photo041/IMG_1072.JPG

^My favorite by far.


Should Zoso host this in his site? I will post this in the e30DIY section.

[straight6pwr]

hey zozo, this is off topic, but i saw you have the write up on control arms so i know youve done it yourself:
how the hell did you get the inner ball joint nut off of on the control arm? im doing the control arms know and thats the only one that wont give. even with the sway bar off there is not enough room to get any torque from a tiny wrench! i saw that's all you used. im stuck in a rut if i cant get it off. ive used penetrating oil and a torch and so far nothing. thanks for any advise you can give, everything has went smoothly until that little guy.

[m42technic]

why does bmw make what should be a super easy job, a pain in the ass?

Changing a t-stat isnt a pain in the ass, by any means.

[FredK]

I like this pic

http://numassmontring.com/photogallery/photo041/IMG_1093.JPG

fruit punch xxx!

[Zoso]

I like this pic

http://numassmontring.com/photogallery/photo041/IMG_1093.JPG

fruit punch xxx!

Beau juice? :D

Nice work Snarcher! I love high resolution pictures on writeups. Don't you just hate it when you see a writeup (or in Bentley) and you can't tell what the hell is going on in the small, blurry, B&W picture?

Is there any reason you decided not to drain the block? Overall, the procedure looks much easier on the M20. I'm jealous! Then again, the procedure would have been easier for me on the M42 if I was able to get the fan off. I didn't have the right tools for the job. I hate that.

[Zoso]

hey zozo, this is off topic, but i saw you have the write up on control arms so i know youve done it yourself:
how the hell did you get the inner ball joint nut off of on the control arm? im doing the control arms know and thats the only one that wont give. even with the sway bar off there is not enough room to get any torque from a tiny wrench! i saw that's all you used. im stuck in a rut if i cant get it off. ive used penetrating oil and a torch and so far nothing. thanks for any advise you can give, everything has went smoothly until that little guy.

Th inner ball joint on the passenger side is such a bitch.

The best way to get it off is to use a crowsfoot wrench:
http://www.toolking.com/images/Products/biggp89072.jpg

Of course I never seem to have the right tool for the job so I had to take off my heatshield and sway bar to gain extra room. With that extra room, I was able to cram a socket wrench in from below:
http://zoso.no-ip.org/images/318i-control-arm/ca-bj3.jpg

My friend happened to have his socket wrench kit with him when I did this job. His wrenches were more fine than mine and I think this really helped because the space the wrench had to turn seemed like a fraction of a degree. You can see that there is barely any room in there to get any torque on the wrench. It was a real bitch of a job.

Once I had that loosened just a little bit, I was able to get it from above with the crazy string of extenders, U-joints, and a socket.

My best advice is to go out and get the crowsfoot. There is no substitute for the right tool for the job.

Good luck.

[straight6pwr]

Th inner ball joint on the passenger side is such a bitch.

The best way to get it off is to use a crowsfoot wrench:
http://www.toolking.com/images/Products/biggp89072.jpg

Of course I never seem to have the right tool for the job so I had to take off my heatshield and sway bar to gain extra room. With that extra room, I was able to cram a socket wrench in from below:
http://zoso.no-ip.org/images/318i-control-arm/ca-bj3.jpg

My friend happened to have his socket wrench kit with him when I did this job. His wrenches were more fine than mine and I think this really helped because the space the wrench had to turn seemed like a fraction of a degree. You can see that there is barely any room in there to get any torque on the wrench. It was a real bitch of a job.

Once I had that loosened just a little bit, I was able to get it from above with the crazy string of extenders, U-joints, and a socket.

My best advice is to go out and get the crowsfoot. There is no substitute for the right tool for the job.

Good luck.

worked like a charm, thanks! and amazingly i was able to pull out the control arm from the CAB, thanks again for the amazing write ups

[Zoso]

glad I could help! I should mention the crowsfoot wrench in my writeup....

[ohnoes]

This is a wonderful write-up. Zoso, you had the exact same problems I did when I did this. I wish I had seen this write-up when I did my t-stat. :(

[BavarianMtoWrkz]

I cant seem to get the thermostat housing off..it looks solid, What now????

[BavarianMtoWrkz]

Dope, never mind, I lossened the wrong bolt,s o there was atill 1 of 4 that needed to be removed.
Came Right...