coolant/overheating probs bmw 528i 1996

Radiator OK?

If you are SURE about the pump and the thermostat, and I would not be sure about them if I were you, your choices then come down to a clogged radiator and a clogged block.

How did you check the pump and the thermostat? If you put your hand on the radiator, does it get warm? Does it get warm in some places and not in others?

If you disconnect the bottom hose from the radiator (cold, obviously), does water pour out of the radiator or does it slowly trickle out?

Has the water pump ever failed before? Water pump failures that leave debris in the system are a big issue.

--scott

What's the history of the car's cooling system service? Did you just change the coolant? It's possible to considerably underfill the system if you fail to follow procedure. Also, with a 12 year old machine, it's possible the water passages are blocked by the accumulation of corrosion in them.

If the system's been bled and full to capacity, it might be door number two.

BMW used to recommend coolant change every two years from manufacture date. It's now 4 years, but I suspect that's a nod to the cost of "free" maintenance, not a change in the vehicle or coolant properties.

Over-the-counter coolants are not recommended and can contribute to the problem. So, it's possible a failure to change the coolant frequently or with the wrong coolant has clogged the cooling passages. Given the difficulty and expense of fixing the problem, I'd check and recheck everything else first.

R / John

hi there guys,many thanks for yout replies,i do appreciate the concern.believe it or not it was a massive airlock in the system.i had always been lead to believe these bm.s could be real pigs to bleed but felt i had done everything right. i decided to persevere with bleeding trying a couple of differant methods and sure enough after 2 days of trying,i blead her succesfully and have since had no probs whatsoever,thanks again!!

"ksdawg01" wrote: > hi,can anyone help.bmw528i 1996. she is overheating,checked > thermostat-ok,checked waterpump-ok water does,nt seem to be > getting around the system. we tried bleeding and got alot of > steam.going to do compression test tomorrow but no signs of > head gasket,ie:water in oil,oil in water,white emmission from > exhaust. we are stumped.anyone have experience wth this . all > help very gratefully received. many thanks. steve