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Old 11-12-2012, 07:42 PM
SFbay SFbay is offline
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Location: SF
Join Date: Mar 2012
Posts: 893
Mein Auto: BMW 745i
Cannot get the air out of the cooling system! Weird

Hi everyone, very important thing here!
Just recently noticed that my temp went to 107-108C, no overheating, but my tranny was acting up while driving in traffic!!! Guess what???
Inpa says 98-102C tranny temp!!
So I checked my radiator and it was only half hot, lower side completely cold!!!
Ok, air in the system? Tried TIS procedure and it didn't do anything. Yes I have new aux water pump.
Installed new tstat and still same thing, water pump is almost new. Wheep hole was fixed too! No leaks anywhere!
Removed tstat and all is good- tranny temp is good never overheats.
Once I put it back same thing is back!
So... Why it's so important?? Bc I just saw my friends car 87k recently he replaced his tranny and its almost same thing!! His car is almost 110C.
His engine is leaking everywhere.
Well, and I saw another 745 160mls with normal hot radiator everywhere and his temp would never go any higher than 102-105, original tranny and engine valve cover gaskets no leaks, only alt bracket seal.
This air in the system will destroy your engine and tranny pretty quick!
So bmw self bleeding system is not working sometimes??? So?? I'm trying to understand if anyone had this issue??
I mean you might have the same problem without even knowing about it.
Simply check if your radiator is hot everywhere after you drive with normal 105 temp.
Needless to mention that it will kill your alternator bc it's water cooled and getting coolant from the tranny cooling heat exchanger.
Pretty much 90% engine and tranny issues described here is all related to this problem.

Last edited by SFbay; 11-12-2012 at 09:40 PM.
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