M20 Overheating - Where do I start?

[MrSlacker]

Picked up a '90 325iX with 213K miles from the auction. No prior service history. After letting the car idle for about 25min, needle was all the way in the red. Popped the hood and the AUX fan wasnt even moving. I will be doing water pump, timing belt, valve cover, spark plugs and coolant flush to prepare it for the winter DD duties. What should I look at and / or replace to start diagnosing the overheating issue?


UPDATE: I did timing belt, water pump, thermostat and a coolant flush and she runs great! No overheating, no issues at all!

[LJ851]

Add thermostat to your list, diagnose AUX fan, verify engine fan is functioning.

Check cooling system for leaks first.

[Cronopoulos]

Add thermostat to your list, diagnose AUX fan, verify engine fan is functioning.

Check cooling system for leaks first.

BOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOM :hitler:

This!

[Ceeker]

the car shouldn't overheat with the aux fan off unless you put the a/c on and the aux fan doesn't come on. However, check you fan clutch. Take a newspaper rolled up and stick it into the fan when the car is warm if the fan stops spinning you need a new clutch. Also check to make sure the coolant system is bled properly and that your thermostat is working correctly. if you let the car idle in the red for any prolonged period of time there is a very good chance you might have already warped the head. Keep you eyes open for coolant in the oil or any leaks or coolant loss. newer let the m20 head go into the red. GL.

[urbancynic]

Check the fan switches in the radiator. Also check the fan clutch. I bet the fan clutch is part of your problem.

Also check the thermostat, and the cap.

[bloodshot-e30]

mine did this.... but it was cracked head

[MrSlacker]

Cool. Thanks everyone. I really hope there is no permanent damage :-/