Thanks for the post! (archive)

I just took a look at my old tank and the new one I installed. You are right! Hopefully my problems are gone. I went ahead and replaced my thermostat while I was in there just in case that was the reason for the overheating. She's running great again now!

Salts

hey
i have a 95 740i , i had the same problem almost a month ago. from observation the expansion tank cracked on the side facing the engine along the slightly raised ridge just about the middle of the tank. i believe the repeated expansion action and heat on the tank over the years weakened the tank along the ridge causing it to eventually give in to the high pressure. The new replacement tank however has no ridge similar to the original factory tanks and i believe this should fix or reduce the chances of the tank ever failing .

fellow 7er thanks

I recently brought my car into the dealer so they could top off my coolant as I was getting the error message. A few weeks later and I get the coolant level message and temperature warning. Bottom line...I found that the coolant tank craked on the side wall and would not allow me to fill the system. I am heading to the dealer first thing in the AM to get a new tank and install it myself. Any ideas on why the tank cracked? I am guesing built up pressure from air in the tank. Anybody else had this problem?

Salts

Scott, Thanks for all of your help and information. You are a true asset to this board. Hopefully I won't have to bother you any more or atleast for a long time.

The bearings were fine, but the impeller had a metal piece wrapped around it. The metal piece looked like it was part of the side wall of the waterpump. I don't know how the impeller even turned. Amazingly the temperature gauge never went up at any time. Does it actually work?

I guess why the car idled roughly is because the metal piece caused an extra load, and then when the AC compressor kicked on it cause too much of a load. Only a guess.

Anyway, thanks to all as this has saved me quite a lot of money by not having the dealer continue his guessing game.

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