Strange coolant vomit.

[ssimms]

Hi,

1992 535i 5sp. 146,000 well care for miles. Never overheated in my ownership, waterpump,radiator fine. Drove it home Friday last and Saturday morning came out to the garage to find coolant underneath (couple of quarts).
So I leave it alone until yesterday to troubleshoot problem.
a)
I find the overflow tank is empty (that explains the 2 quarts on the floor)
b)
I start the car and don't see any obvious leaks or hear any unusual noises.(only ran for 2-3 minutes)

So, since my wife has complained about the weak heat in the car lately I decide I probably need a new heater valve or aux water pump.
I take them out to find nothing wrong with either one as far as I can tell. The heater valves energize as they should and I can hear the pistons rise and drop as they should. I took it apart to verify nothing broken on the inside and no apparent leak on the outside like a crack or something.
The aux. water pump also will run when connected to 12volts and no strange noises or cracks in it either.
The hoses I removed at one end all look ok. So not any obvious broken hoses or splits etc.
Any ideas for my next steps? I would appreciate the assistance. I can't say that in my 26 years of BMW maintanence I have ever seen a car throw-up it's coolant without being hot or overheated.
Thanks in advance for any assistance or suggestions.

Scott

[dternst]

Checkout this thread:

http://www.bimmer.info/forum/showthread.php?t=19828

[ssimms]

Checkout this thread:

http://www.bimmer.info/forum/showthread.php?t=19828

Thanks, but, since my car hasn't been getting hot or overheated I don't think this is much help. by the way I searched through 60 or so topics before starting this thread.

[Blitzkrieg Bob]

the back of the engine? more towards the trans?

Could be the heater core.

It would leak out from the lower fire wall .

[ssimms]

Yes it was closer to the firewall. That would be a bummer. Does anyone know how to check their condition without removing center dash? The coolant return pipes are sitting full with coolant since I removed the hoses last night. I would have thought that if the heater core was leaking it wouldn't hold coolant.
Thank you so much for the ideas.

[Scott H]

the drains for the a/c evaporation and the heater core leaks are two tubes that run out each side of the tranny tunnel. Stick your head under there and see if those tubes have dried or evaporated coolant. Do you smell coolant in the cabin when you run the heater? The plastic lines that run to the heater core have been known to crack as well....

Yes it was closer to the firewall. That would be a bummer. Does anyone know how to check their condition without removing center dash? The coolant return pipes are sitting full with coolant since I removed the hoses last night. I would have thought that if the heater core was leaking it wouldn't hold coolant.
Thank you so much for the ideas.

[zmuff]

Did you take a good look at the overflow tank where the hose is attached? Mine had cracked about 3/4 of the way around but it was hard to see, the hose covered it up by about 1/8 inch. It definitely puked out it's guts on the floor. It would be a whole lot easier to fix too. Good luck.

[Alexlind123]

I recently replaced my expansion tank as well. The plastic give out after about 15 years.

[ssimms]

Thanks all, I have some more troubleshooting to do with all of your suggestions. Thanks again. As usual you are all aces in my book.

[ssimms]

the drains for the a/c evaporation and the heater core leaks are two tubes that run out each side of the tranny tunnel. Stick your head under there and see if those tubes have dried or evaporated coolant. Do you smell coolant in the cabin when you run the heater? The plastic lines that run to the heater core have been known to crack as well....

No it doesn't smell at all in the cabin. I am still at a loss.