90Q overheating

[Huw Powell]

> Have a serious overheating problem on my 1988 90Q. Basically overheating 
> and then dumping all it's water. Have just changed thermostat, and have 
> tried radiator cap off my CQ. No change. Fan does come on, but seems to 
> turn off again even when car is still hot, so concentrating on this for 
> now.
> 
> Which sensors drive the radiator fan? Sensor at bottom of radiator?

Yes - it has two outputs, low and high.

> Are 
> there supposed to be 2 speeds for this fan?

Yes.

Your fan is running sometimes, maybe the fan motor is dying?

> The B3 90Q has a 13mm (wrench size) bolt on the primary radiator that acts
> as a bleed screw for the system.

Which should only need to be loosened, I think. It has a small hole in 
it to allow air out after it's out a turn or two.

-- 
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/