Cooling Fans? When are they supposed to Run?

Subject: Cooling Fans? When are they supposed to Run? Mon Mar 31, 2014 9:39 pm

I have a 95 Supercharged Riviera. Can someone tell me if the temp gauge reads in the red and you shut the engine off, are the fans supposed to run until temp drops? Seems like they should as I have had other vehicles that the fans continue to run for a bit after the car is shut off? If they are supposed to what do I need to fix to make sure they do. Thanks

Do the fans turn on with the engine running?

I would be more worried about why the coolant temp rises into the red, than why the fans aren't kicking on after shut down. The temp gauge shouldn't go much above 1/2 way (~200ºF). Check your t-stat, coolant condition, and radiator first. I don't think the fans, or lack of, are causing your overheating situation.

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They do run at times but only off and on cycles. I guess I was using that as a reference to where I believe the fans might run if the car is shut off with a temp on the higher side. So to make it more simple do the fans on a 95 ever run when the car is shut off?

Not sure without reviewing the factory service manual (I don't have one for a '95). I wouldn't expect the fans to run with the key off though. It wouldn't help the engine unless coolant was flowing. No water pump, don't bother with the fans.

I've seen cars have their fans run after the car was shut off for some period of time, and I think I recall the manual warns about disconnecting the battery during maintenance around the fans and cautions they could activate at any time.

But I haven't seen them run like that on my 95 yet.

I had a vehicle that had that warning also, might have been a Town & Country van. Seems like a pretty unsafe situation to me.

Here's the page from the 1995 Buick Riviera Owners Manual where it warns that the fans could start at any time, even with the engine off.

Cooling Fans? When are they supposed to Run? 1995-r10

Cooling Fans? When are they supposed to Run? 1995-r10

If you have the key on, the fans could start for a variety of reasons. Since people often look under the hood with the key on, the warning is necessary. I'm pretty certain the fans will not run with the key off.

Some people mod the Series II PCM to enable fans to stay on after the key is off, so it's possible to do in a non-stock configuration. But if it's stock and you turn the key off, they will stay off.

Well again, I can't say for certain about the Series I or II engines, but I've been around a fair share of cars that will keep their fans running after the car is shut off and the driver has left the building.... the car sitting in the parking space, fans running, all locked up.