i really need help with the overheating

[blasito1973]

as i posted before my car is overheating , when i got it i didnt had the fan shroud , the auxiliar fan only worked with the ac swithch because the temp switch was disconected and i was not aware of this but it didnt overheated , then i got the fan shroud and evrithing was ok then it overheated the mechanik took out the thermostat and it was ok , but last week it overheated , we took out the radiator hadit tested and i was told that it was ok,we tested it and it overheated so i changed the cap with a new one and asembled evrithing again , it overheated ,replaced the seals of the reservoir because i noticed it was driping from the bottom , evry time i has followed the recomendations for purge and i have used so far like 6 or 7 bottles of peak antifreeze , i dont want to keep throwing away my money , , also i was told that the water pump is working , the fan clutch is working , last time even the aux fan was on the wole time i drove about 10 miles stopped had diner and go back home but it overheated again pls , any thougths about how to fix what to check for
thanks for the help

[putyoursoxon]

they say the pump and thermostat are working, but sounds like thermostat isn't working, i would check if thermostat is working, if the hoses are hot are running temp then its working, if the top hose is cool then theres no flow

[mcoupemindy]

I have no idea where to begin on this one ...

First, you need to only use BWM coolant. Others have been shown to pit the engine blocks after time. You said you have used massive amounts of coolant, did you ever think you might be burning some of that off?

Second, if you've overheated it more than once, odds are that you have destroyed your head gasket and that will needs replaced. If the head gasket is blown, you're never going to be able to bleed the system properly. Have you had the system pressure tested?

Third, instead of testing parts, you need to start replacing them. Testing the cooling system in a Z3 is pissing money away. THEY ALL FAIL. Just bite the bullet, and replace all the hoses, radiator, expansion tank, waterpump, thermostat and thermostat housing.

Oh yeah, it sounds like you so called "mechanic" doesn't know anything. How about taking it to a BMW dealer where they actually know these cars?

[2kredz3]

I would say the T-stat s not working. If a car is going 30+ mph with out being at high RPMS it will being going fast enough that the two fans done matter. so if its over heating while moving then either the t-stat is not working or your radiator is plugged.

[M Roady]

Why would a mechanic take out your thermostat without replacing it? Get a new thermostat and mechanic, but not in that order. As for your antifreeze loss I'm not sure. If it were the head gasket I'd think you'd know because you'd be driving a fog machine. Replace the termostat, maybe once you get the overheating under control perhaps your coolant will stop dissappearing.

[lil z3]

Please specify which motor. The 4 cyclinders and the 6 cyclinders have differant issues and differant fan set-ups. Also how do you know your overheating? Are you blowing steam or is the temp gauge maxed? If the gauge is maxed, the temp probe may be at fault.

[blasito1973]

i went to the dealership and bougth the thermostat and cap

[2kredz3]

Kwel, let us know if that fixes it.

[pwhitt]

dude - i have no idea how to help re the problems with the cooling system, but i just noticed that you're in monterrey.

i spent about eight months there last year - how is that traffic on gomez-morin? you know when i first moved there i was at first completely terrified of the traffic... after a week i *loved* driving there! god, that city is like a racing video game!

that's a beautiful city man, hopefully i'll see it again on business.

[blasito1973]

well it didnt solved it overheated again so tomorrow i am going to get a new water pump , and yes it is an ok city myself i was born in mexico city and came here to study and never left

[2kredz3]

sorry to hear that. . .hopefully the water pump will fix it.

[edwjmcgrath]

Not to threadjack but all of these posts about overheating, etc are getting me freaked.
I've got a 96 1.9 with 50k miles with no overheating issues. All cooling equipment is original.
Should I do a cooling overhaul?

[fmcfad01]

Not to threadjack but all of these posts about overheating, etc are getting me freaked.
I've got a 96 1.9 with 50k miles with no overheating issues. All cooling equipment is original.
Should I do a cooling overhaul?

I just did a cooling overhaul at 90k on my ///M - replaced everything related to cooling and retrofitted an S54 ratiator/oil cooler system onto the car. I'd say you have time to go. I did mine preventively as well, no problems to report.

[bimmerZ5]

you really should diagnose the problem rather than throw parts at it...

for one, not bleeding all the air out of the cooling system will cause you to overheat. it could be as simple as that.

if you're losing coolant all the time and you don't see it dripping on the floor, you could have a head gasket leak. if you've overheated one too many times for too long, you could have a warped or cracked head and that's where your coolant is getting into the cylinders or elsewhere.

after you put your cooling system together, either pressure or vacuum test the system to make sure it's sealed. if you can't hold pressure or vacuum, then you've got a leak and that needs to be addressed. if you use a vacuum test, make sure you've drained the coolant from the heater, engine, and radiator or you'll just boil any remaining coolant and lose vacuum.

if you're concerned about your thermostat not working, you can test it by throwing it in water and heating up the water until you hit the right temp and see if it is working.

I don't know about I-4 water pumps, but usually before they completely fail, they'll start weeping cooling out the weep hole and this is noticeable by looking for dried coolant (white powder) around your fan.

[blasito1973]

in my first car i blew a couple of head gaskets and there was the same symptoms , water on the oil , or oil in the water and water or oil or both on spark plugs , none of this is in my car but i will try to get the car to a place where they can check the pressure of the system , the coolant i am losing is when the car heats up it throws it via the radiator cap , and the first time i also think that was throwing a little driping in the lower part of the bottle , i replaced both of the ruber gaskets the big one in the botttom and the little one at the top and now i only have seed that it looses it in the cap .

[blasito1973]

and i read about the oem pumps have rotors made of plastic and that some times they crack and do not provide proper circulation of the water , so i am going to take it appart to see the phisical condition of it

[mcoupemindy]

and i read about the oem pumps have rotors made of plastic and that some times they crack and do not provide proper circulation of the water , so i am going to take it appart to see the phisical condition of it

Read my post above. Quit being cheap and start replacing parts.

[blasito1973]

yes thats exactly what i am going to do

[2kredz3]

Not to threadjack but all of these posts about overheating, etc are getting me freaked.
I've got a 96 1.9 with 50k miles with no overheating issues. All cooling equipment is original.
Should I do a cooling overhaul?

do a little at a time water pump to start with then t-stat hoses belts radiator last

[blasito1973]

he removed the pump and told that it was ok , he is going to make a pressure test to check the head gasket

[blasito1973]

and other thing last nigth i drove to the super market it was about 59 f and it is like 8 blocks away , the gauge didnt make it to the end of hthe blue part of the dial and when i stopped it threw a little coolant in the way over there i had the heater on and it was blowing hot air

[jr1966]

Not to threadjack but all of these posts about overheating, etc are getting me freaked.
I've got a 96 1.9 with 50k miles with no overheating issues. All cooling equipment is original.
Should I do a cooling overhaul?

Check this thread that I just posted.

http://forums.bimmerforums.com/forum...d.php?t=940737

To the OP, check these 2 plastic parts that I mentioned in this thread for leaks.

[MikeHsu]

I scanned this thread, and I would say its the thermostat and the waterpump. I had the same problem and I looked at the thermostat/waterpump and it looked fine but it really wasn't. I would give it a try.

[blasito1973]

i didnt check with the mechanic today ( had a lot of work ) but what i noticed in the water pump was a little salt like in the gasket and little on the hole at the front but nothing that would indicate a leak i will show the mechanic tomorrow the pics and coment to him about the water pump , maybe i will order it from e bay here in mexico in the bmw they asked for 120 dls plus the core , and in ebay the high flow are about 190 i think and the regular ones are from 40 to 80 so maybe i will order one in the meantime

[blasito1973]

here is what happend the new mechanic filled out the radiator started the car and it was working great for about 3 r 4 hours on his shop the aux fan was woring like it was supposed going in and out , i told him to test the car ad he went to his house and then it overheated ,it looks like the radiator guy that it was supposed to check the radiator didnt do anithing the mechanic toldme that the same thing happend to him , the fan didnt work , , he checked the hoses and they whee hot but the great surprise was tht the radiator was cool he is going to take it out and send it to haveit tested he thinks it is cloged , i will post as soon as i have more news