BMW cooling system

GWENLOUQUE

MEMBER
2004 BMW 330
6 CYL
2WD
AUTOMATIC
100,000 MILES

BMW 2004 330i automatic. About a week ago I put "stop leak" in my radiator because I had a hairline fracture in my expansion tank. I just replaced my expansion tank and transmission thermosat and took it for a test drive and it ran hot, but the coolant wasn't hot at all. Any clue what the problem is?

5 Replies

DOCHAGERTY

MECHANIC
9,601 POSTS

The stop leak stuff is not a good idea to use, you may have plugged up the steam holes in the head gasket.

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Saturday, January 8th, 2011 AT 8:56 PM

DOCHAGERTY

MECHANIC
9,601 POSTS

There is also an air bleerer screw on the top of the expansion tank, it needs to be opened when filling the system to allow the air trapped in the system to escape, was this done?

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Saturday, January 8th, 2011 AT 8:59 PM

GWENLOUQUE

MEMBER
3 POSTS

Just bled the system and no longer overheating, but now the heater will not work.

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Saturday, January 8th, 2011 AT 9:13 PM

GWENLOUQUE

MEMBER
3 POSTS

The heater will work on feet and vents by winshield fine. Nice and warm but about 70degrees on face vents. Any clue? The bleeding worked!

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Saturday, January 8th, 2011 AT 9:32 PM

DOCHAGERTY

MECHANIC
9,601 POSTS

You are seeing normal operation, the center vents are not going to blow hot air, this is a strategy that BMW has used for quite some time. You must have recently aquired the car, yes?