Strange e36 323 overheating problem.

[TDP 0]

Hey all,

Sorry about this, bit of a lengthy story.

A mate of mine recently drove us from Auckland to Whakatane in his automatic '95 E36 323. We were just south of Paeroa when the temperature gauge moved into the red and the warning light lit up. We duly stopped, opened the bonnet and looked, fairly pointlessly, at the engine. It appeared fine, there was a little bit of coolant that appeared to have vented, but the engine itself was not particularly hot and there were no drips or signs of leakage. We drove back to Paeroa and had bad pies at an unusually spacious cafe, thus giving the car time to cool down. I took the cap off and inspected the radiator fluid. It was plentiful and beautifully clean and green. A pooling of our mechanical knowledge revealed that collectively, we suspected wheels might be round, but weren't totally sure and we certainly had no idea about engine cooling. We decided that ignorance was bliss and pushed on to Whakatane. The gauge made the occasional foray into the red again but would very quickly drop back down to about halfway and the light did not come back on.

After a very enjoyable 21st, we returned to Auckland via Rotorua. This time the light would come on quite regularly, especially under load (ie: climbing a hill, overtaking pillocks who do 50 if the road curves even slightly). We discovered that if the light came on and we then put the car into neutral and coasted along for a few seconds the light would quickly go out and the gauge would return to about halfway. We also discovered that when the car was overheating, the cabin heater was not working. It was pumping, at best, lukewarm air. As soon as the light went out the heater would start working again. The nearer we got to Auckland the shorter the intervals between overheating periods became. Another fact that seemed odd and that may or may not be be pertinent is that the CDs coming out of the dash mounted player were unusually hot, to the point where you could smell them. Interestingly, the car itself never smelt hot, or steamed or even looked hot, although by the time we go to Auckland it was venting a steady drip of coolant a second onto the petrol station forecourt.

Initially I thought it may be an electrical gremlin giving a false indication, then I thought it may be a sticky thermostat, then I thought that maybe the water-pump drive belt was slipping under load (although it never sounded like a slipping belt) finally I'm beginning to wonder if the water-pump isn't slowly dying (flogged out bearing causing it to jam under load?).

Thoughts, experiences, ideas gratefully received.

[Jonty m50e30 0]

Water pump would be my first thought, some of the M50/52's have a plastic impeller which can be troublesome, doesn't really explain the intermittent problem however when not under load maybe as you suggest the pump works and when you give it some punch it gives up the ghost. This is where I would start any way. Could aslso explain the heater not working as it is reliant on the water to the heater unit I think. Cant help with the CD's must be the Phat Beats!

[TDP 0]

Water pump would be my first thought, some of the M50/52's have a plastic impeller which can be troublesome, doesn't really explain the intermittent problem however when not under load maybe as you suggest the pump works and when you give it some punch it gives up the ghost. This is where I would start any way. Could aslso explain the heater not working as it is reliant on the water to the heater unit I think. Cant help with the CD's must be the Phat Beats!

Cheers! Yeah I thought the heater issue was connected to the overheating issue. I'll tell him to have the pump looked at. The car has a mechanical warranty so it sould definitely cover that.

[*Glenn* 854]

I would check the pump impellor first- commom problem, the plastic impellor is probably broken or loose on the shaft. And change the thermostat now after all these overheat situations.

Cheers

Glenn

[TDP 0]

I would check the pump impellor first- commom problem, the plastic impellor is probably broken or loose on the shaft. And change the thermostat now after all these overheat situations.

Cheers

Glenn

Will do. Thank you.

[TDP 0]

If it's of any interest to anybody. It turns out it was the water-pump that was the problem here.

My friend just had it and the thermostat replaced. The pump was apparently on the verge of total failure.

Just looking through this section it seems that overheating is a pretty common problem with all sorts of BMWs. Interesting.