One of the first jobs I did on the 850 was to replace the OEM (white) coolant expansion tank. That was about 14 years ago. After the last drive, I opened the hood to connect the battery tender and heard an ominous hissing. The black tank was leaking steam from the place indicated in the photo (where the top is joined to the body).
Just FYI.
46258015754_7503b12dde_c.jpg
Mark in mid-MO
1993 BMW 850Ci 6-speed
2011 Cadi CTS coupe 6-speed
If you haven't already - change the cap - it contains a pressure-relief valve and may have failed....
Timm..2007 E64 650i Individual Sport..1999 E31 840ci Individual Sport..ex owner of 2000 E38 740..1999 E38 740i V8 M62..1998 E38 735i V8..1993 E32 730i V8..1988 E28 518i
My BMW Repair YouTube Channel
My Current 840ci Sport Individual
My Current 650ci Sport Individual
My E31 Repair and Information Website
My E38 Repair and Information Website
My E63/E64 Repair and Information Website
Chase - Heroes to a generation
Thanks, Timm!
Mark in mid-MO
1993 BMW 850Ci 6-speed
2011 Cadi CTS coupe 6-speed
The black plastic in the cooling system components (radiator and reservoir) weakens with age, pressure and temperature.
I would always suggest to prevent cooling system "on the road" failures that these components be replaced as part of a maintenance schedule and 14 years is much too long.
Bookmarks