528i Temperature/Electrical ?

[moremenow]

1997 528i with 85,000. Generally has run well, but has periodic 'electrical' problems (e.g., engine light stays on even after 2-3 shop visits regarding sensors).

Anyway, in past 30 days have experienced temperature gauge go from normal (center) to all the way hot (red light on). It occurs on acceleration and ramps and typically in first 10 min of driving, but not always. It moves to red for 20 seconds then immediately moves back to center. No heat - no smoke.

Dealer sucks - 3 week wait (monopoly status). Any thoughts? Coolant? Other fluids low? or just electrical quirk? Thanks.

[moremenow]

Another thought. Not just a general "electrical problem", but noticing that the temperature gauge pegs into the red area before coming back within 10 minutes of getting in the car.

In other words, is it possible the car IS getting hot, but the sensor that turns on the fans, coolant, or whatever are not being triggered when they should. They do come on to cool it down, but always 30 seconds after the engine starts to heat. Does this make sense?

[Jared at Pelican Parts]

This sounds like either a ground problem or a faulty coolant temperature sensor. This will also cause problems with driveability when the engine is cold.

[stealthn]

Sounds like a ground fault to me too...

[moremenow]

Turns out after a mechanic's diagnostic, that the plastic propeller in the BMW's water pump sometimes gets overheated, bends, and loses pressure as a 'fan'.

Thanks for your ideas.