Overheating problem on my 92 525i

[bjl4776]

Figures, i move 1500 miles north and the average temp is in the 30s and my car starts overheating. The radiator and the waterpump are about two years old, and the t-stat housing is new so im assuming the t-stat was also replaced, but there is no coolant in the oil or vice versa, so wtf could it be. I doubt its a fan cause its so cold out, and ideas or ways to find out, thanks.

[632 Regal]

need more info...does it overheat when stopped/traffic/highway? Was or is it low on fluid, if it was did you add fluid? Did you bleed it/properly bleed it? Etc, need lots of info to be able to do a guess.

[bjl4776]

It overheats all of the time, in traffic and cruising whether it be at 45 or 80. Sometimes it cools down when im at speeds and sometimes it doesnt. I flushed the coolant about a year ago, and bleed it properly. Coolant level is fine. When it cools down on the highway, it overheats again when i get off. I know its because of the wind on the highway, but sometimes the wind doesn't cool it down on the highway.

[632 Regal]

after you confirm weather that works or not Id say listen to the clutch fan when you rev the engine to about 2k rpms, should sound like a school bus. Other than that since youre sure theres NO air in the system I'd say you have air in the system thats not letting the coolant flow. Air pocket at the waterpump.

[bjl4776]

Ok, Ill check that out tomorow. How would air get into the system if its been fine for so long, especially since there aren't any appearant leaks and my coolant level isn't low. How would the aux fans make a difference if im not using the aircon anyway.

[nsbone_1988_520i]

Ok, Ill check that out tomorow. How would air get into the system if its been fine for so long, especially since there aren't any appearant leaks and my coolant level isn't low. How would the aux fans make a difference if im not using the aircon anyway.

I had similar sympthon for a while. I changed fan clutch, bleeding etc except T-stat. So recently, i took out the t-stat and noticed the inner valve is smaller than the hole for water passage it supposed to close on the t-stat housing. What's this valve for? By properly closing the hole will "force" the water pump to push the water to the radiator rather just circulate inside the engine...

I have some t-stat's in hand, so i chosed the right size and also i put the t-stat in the boiled water and see how long it will elongated, and use this length to see if will close the hole in the housing. Once confirmed, then i replaced the t-stat and have no problem since with the overheating...

So maybe this is something you could also look into...

[bimmerd00d]

i had this problem last year. If you turn off the heater, re-bleed your system, does it still overheat? I bet your aux pump/heater core is leaking. turning the heat off while bleeding bypasses that, isolating your problem to one of those two.