Cooling Fan

paolo137 · September 4, 2006

Seldom have I heard the engine cooling fan working since I got the car 12 months ago.

But every time I heard it working, I noticed it would stop along with the engine, while I expected it to keep on turning for a while even with the engine off.

Is that up to the actual temperature of the engine/coolant, or could there be a malfunction?

Thanks for your comments.

lexicon · September 4, 2006

It's normal for the fan to stop when you turn the ignition off.

Some manufacturers allow the fan to run with the ignition off, but I've never understood the reason. If the engine is not running then the coolant is not being circulated, so you would only be cooling the radiator - seems pointless.

paolo137 · September 4, 2006

You do have a good point there.

As you said, some other manufacturers think differently (I remember the fan of the mighty Sierra Cosworth running for ages... ), and I thought a little fresh air under the bonnet would be better than anything at all.

Anyway thanks for your reply, my friend, I feel reassured!

ROYT · September 4, 2006

Think sometimes engines with turbos have very high under bonnet temperatures when everything is tightlly

packed in and this is why some fans run after ignition switched off.....

Cymro · September 4, 2006

On my TT there's always about 4 minutes of whirring & gurgling after I switch off. I didn't know why. Prompted by this thread, I asked on the TT website (it's brilliant -

http://www.tt-forum.co.uk/ttforumbbs/viewforum.php?f=2 )

and was immediately advised by the Vice-Chairman of the TT Owners' Club that "It's a water pump for cooling the turbo...".

Which begs the question: "Why isn't it necessary on the RX?"

lexicon · September 4, 2006

"It's a water pump for cooling the turbo...".
Which begs the question: "Why isn't it necessary on the RX?"

You answered your own question - it isn't turbo'd.

I can see there would be benefit on a turbo, especially if it's actively cooled by pumped water.

Maybe all the parked cars I've passed with their fans running were turbo-charged - never thought about that!

Sagitar · September 4, 2006

It's normal for the fan to stop when you turn the ignition off.
Some manufacturers allow the fan to run with the ignition off, but I've never understood the reason. If the engine is not running then the coolant is not being circulated, so you would only be cooling the radiator - seems pointless.

I had a Nissan Maxima on which the fans continued to run after the ignition was turned off. It was not unusual to hear the fans start up in the garage, some time after I had parked. Presumably because heat had soaked through to the thermostat.

There was a notice under the bonnet that warned you to disconnect the fans when working in there and there was a very simple plug-in connector on the external radiator thermostat to enable this.

paolo137 · September 5, 2006

I had always thought that the turbo fans were cooled by oil...

I remember that the first Lancia Delta Integrale's were a bit of a nightmare for their proud owners, because they would drive their beauties to the limit, brake leaving half their tires on the ground, turn ignition off for a caffe' with the boys and...

the two turbo fans would overheat and get stuck :D