e32 overheating... (1992)

Our e32 has started to overheat. It has not overheated in the past. After about 10 minutes at idle, it's maxed out. Driving doesn't make it any worse, or better.
There is plenty of coolant. We put a new thermostat in when we changed the belts & seals. Is it possible that the thermostat is bad? Opening the bleed screw does not release air.
Is there a way to test, on the car, the thermostat? In our subaru it's possible to remove the cap, start the car, and watch the coolant be moved. In the bmw -- this doesn't seem possible.
Also; the fan clutch looks newer (ie: replaced) but still free-spun once the car overheated. Could this cause the car to overheat this quickly?
Lastly; the car is "chipped" -- Could this possibly cause the car to overheat? I can't see how this is possible; but that's the only non-standard thing I can think of.
Thanks -josh
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It may not be properly bled. I recently had a similar issue on my E38. On that car you have to bleed it with the radiator cap removed and only put it on afterwards. Otherwise presumably there's too much -ve pressure to bleed the system.

It's not. But you should feel the radiator hose warm up once it's open.

A bad fan clutch would cause overheating at idle, not when the car is driven at any reasonable speed.

No.
I suspect the system hasn't been bled properly.
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Thanks for the info. I'll read the book on how to bleed it properly.... I have to replace the cowling (it's there, just a tad loose) so that would be the ideal time to replace the fan clutch too. It should get impossible (or at least difficult) to move when hot right? (if the engine is off).
Thanks a lot! -josh
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OK - here's what I've done.
car was cold, turned the bleed screw, a little air came out... just a little. Started the car, and every once in a while I'd re-open it and a little more air would come out. the rad hose on the right-side never got warm... the left side got hot. The radiator barely got hot on the left side; and stayed cool on teh right.
I opened the overflow & occasionally it'd "gurgle" like steam was trying to get past the coolant.
At this point I shut the engine down; and pulled the hose leading to the bottom of the thermostat housing. the fluid was cool to the touch. The coolant IN the thermastat housing was hot.
So There is coolant everywhere.... Well; more places than I'd like now.
So -- I assumed it was the thermostat... I pulled it off & tossed it boiling water.... Let it sit there... Opens at 190, closes at 180 (that's about 87 & 82 celsius) That seems right; but maybe I need a cooler one? 75 or 72 celsius? Or are we still thinking it's not fully bled correctly?
Sadly the aux fan never clicked on either... so I've got a second problem there.... But I do not believe this is the cause -- mostly becuase the one side of the radiator doesn't heat up....
Thanks.
-j

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if the aux fan is not running, I believe that is the problem.
go to http://www.bimmer.info/forum/forumdisplay.php?f  and ask there, they specialise on that engine there... this is a very common topic... ask there and you will get info very fast.
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Thanks!
I'm guessing it's NOT the actual problem, but A problem.
I think the shop put the thermostat in backwards. I put it in "right" (didn't pay attention when I pulled it) and now the car isn't overheating -- infact, it's running COOLER than it did before it was swapped....
However, looking at how those crafty Germans did it -- it looks like they designed it so it really doesn't mater which way it goes in - am I wrong?
I have the manual; and it talks about trouble shooting the aux fan - but I'll ask there just to be sure the manual isn't missing something.....
Cheers -josh

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get a BENTLEY MANUAL FOR THE CAR... OR FOR A E34 535, SAME THING VIRTUALLY! search the bimmerinfo and you'll find TONS! tell them sharkman540 sent you!
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Got one - gotta find my ohm meter...

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SharkmanBMW wrote:

The aux fan will not come on until the coolant temp in the radiator exceeds the switch setpoint. That won't happen until you pump hot coolant into the radiator. I think your water pump isn't pumping.
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Josh Assing wrote:

Sounds like a water pump problem to me.
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Water pump looks new. I could pull it; but since putting the thermostat in the "right way" my overheat problem seems to ahve gone away... Will be retesting today.
-j
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Josh Assing wrote:

Well, that would do it too. If the T-stat is in backwards, the pump pressure will always be trying to close it when it needs to open.
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Hmm. The hoses never seem to generate that much pressure in them, that is to fight the spring.. but I like it! I'm going with that answer.
THe car idled fine for 10 minutes, it "started" to get hot; I gave it a quick blip of the throttle, it cooled right down & stayed steady for another 10....
-j
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We had a bad t-stat in the 00 323 - faught with it while waiting for the tools to come in to remove the fan clutch. Did not bleed it properly the second time and she was quite the moody little german. Went back, pulled the bleeder screw and ran it until coolant came out smoothly, replaced it and she was happy until the new t-stat went in. During this time I topped off the 97 528 and did not think to bleed it. Overheated the next day. Let it cool down, completely filled it back up, removed both bleeder screws and all is well. I have never had a problem like this with the 94 325is and have yet to personally work on the 01 530i but rest assured that if I TOUCH the cooling system on it the bleeder screw is coming out!
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I did the cardboard test on the clutch. Car came up to temp & stayed right where it should. (aux fan didn't kick in -- gotta find my ohm meter).
The clutch stopped very easy -- and actually, had less friction than when it was cold -- I could spin the fan in the opposite direction as the pully w/o a problem. I guess I"ll be ordering a new clutch now... :(
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m30 engine...
OK -- I've now confirmed the clutch is 100% shot. I've confirmed the thermostat opens correctly The aux / electric fan operates correctly.
I still overheat; but not temp wise (as from teh thermostat) ; but by stuff boiling back up thru the resevoir... BUT WAIT!
Before we go telling me I don't have it bled correctly, I'd like to bounce something off you.
Should I be able to stop the water coming out from the thermostat housing with my hand? That little elbow that goes from the water pump to the thermostat housing -- I removed it -- fed water into the pump with a hose, water came out (not fast) from the thermostat housing. I put a rag & my hand over the output from the thermostat housing -- and guess what? NO pressure. None.if there's no pressure there -- how does it force water thru the radiator?
The "piss hose" that feeds from the top of the radiator back to the overflow? barely a trickle.
This is all with NO thermostat in at this point -- trying to maximize water flow --does this all sound like a bad pump?
Before I go ripping the pump off -- can someone explain to me HOW the pump works? is it possible for the impeller to separate from the shaft & sorta spin from friction vs. force?
Is'nt this starting to sound like a bad water pump?
Thanks -j
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