Hey i bought a 528e one time for $225 cause "noone" could figure out why it overheated turns out the waterpump impeller had come off the shaft.... warmup car with water tank cap off look into tank at small hose leading from raditor is it "peeing"{should be}? also did u have this prob prior to replacing tstat? hope this helps. jeff Just did the thermostat on my 535is and still runnin on the hot side of the gauge.Bled system many times.flow seems to be good.The cluch fan seems a little week. I acadently hit while i was bleeding and IT stopped rite in my hand,is that normal or is it shot?it only seem's to cool down when the aux fan comes on. I have the bently on this car. I am just lookin for some addvise on where to start. it only had this prob when sat at idlle for a while like in heavy traffic or at the bank drive in. but it would just touch the red zone never go in it.the little pisser is indeed pissing.im starting to think that it may be the low aux,switch in the radiater what ya think!.being as i never heard that go on, untill she gets to the red, then the high switch kixs in and she cools right down. and as long as i don't run up the r's it will stay about 3/4 to just about the red.