Engine Fan

[VOATMJ1]

Is it normal for the engine fan to engage, whenever I start the engine up when it is cold, like say overnight?

Sometimes it does this and sometimes it doesn't, but most of the time it will. Just curious. It does not stay engaged for very long, maybe like a minute and then goes off.

I was under the impression that the only time that the fan was suppose to engage, was when the engine was hot. This in on a 2000 Sport 4X4 with 30,000 miles. Thanks!

 

[Robb]

Out of curiousity, is the A/C on?

Robb

 

[VOATMJ1]

No, the A/C is off.

 

[Robert]

Yes, your fan should spin all the time your engine is running (unless you have an electric fan). Most fan clutches are designed to freewheel at higher RPMs. At idle your fan should be spinning as fast as your engine is turnning. Even at higher RPMs though the friction is usually enough to keep the fan turning. The fan needs to turn at low RPMs since that is when the air is going the slowest through the radiator. There is more chance for your engine to run hot at slower speeds. At highway speeds (higher RPM) the speed of the air going through the radiator will exceed the speed that the fan can pull it through so the fan tension gets lighter. This helps fuel economy and power.

 

[VOATMJ1]

Ok, thanks for the explaination. I understand that the fan should always free wheel, but I only thought that the fan clutch only locked up when the engine was hot and needed cooling, and not at a cold overnight start up and then disengage after about 30 seconds to a minute and then free wheel.

I had a Bronco, and it never did that, only when the engine was hot and then the fan clutch would engage, when cold it would just free wheel.

I suppose that is a (to quote the most beloved statement from most Ford dealers) "a natural charisteric condition of the Explorer."

Thanks again!