Hi chaps

When stopped after a drive (not neccessarily hard), and with the keys still in (to prevent activation of the alarm/immobiliser), the fan sometimes comes on after a short while. This then stays on for a good few minutes. However, if at any time the keys are removed, the fan stops.

So why is it if the engine/coolant is so hot as to activate the fan and presumably prevent overheating, why does it go off when the keys are removed??????? PS the fan activates normally when stuck in traffic etc

cheers

 

IMHO
The sender unit for the fan (usually a small thermocouple) is responsible, usually located in the rad, block, head or thermostat housing the sender/switch activates the fan when the temp hits the right point. It does not really care if the engine is on or off. The water will heat up due to the car standing still, no airflow through the rad or over the engine so's no heat dissapation. As the temp goes up - the fan cuts in 'till the temp drops below the cut out point.

When you remove the key you cut the power to the circuit. This is not the case on all cars - some Renaults and others fans will cut in with he key removed (circuit live al the time).

Hope this makes sense!



[This message has been edited by Paul Habgood (edited 09 January 2001).]

 

I had a Renault 5 GT Turbo a few years ago - it had a fan that would run for TWENTY minutes after you parked up. For some reason the battery didn't last very long (another story!). The car actually had THREE electrc engine cooling fans - a normal radiator fan, a turbo cooler fan, and an anti-percolation (coffee) fan.

An awful lot of bits under a small bonner, i'll say!

mb