Hey guys-

Despite my constant bombardment of Expedition-related information courtesy of this site, I don't know squat about fan clutches. I understand the basic workings, but I wanted to ask you guys - should my fan always be spinning? No matter what the ambient temperature is, the fan is always spinning when the engine's on. Doesn't matter if it's 80degrees or 10 below 0 - that stupid fan is always doing its thing. Is my fan clutch bad? Shouldn't my fan only be spinning when the engine's hot?

I'm planning on installing one of those flex fans eventually. Any experience with these?

XXL

 

Leave the stocker on, the flex fans don't pull as much air. Your fan will always be spinning some. If you want to see what happens when the temp goes up stick some cardboard in front of the grille and block some airflow, you can see the fan spin faster.

 

I've heard from other people that flex fans don't work as well as regular stock fans do, but are they that bad, or is it just this engine that they don't work well with?

XXL

 

They don't work worth beans on any engine. One of those nice gimmicks like tornado devices that go in the intake, or fuel line magnets...

There are some OEM flex fans that were used on some engines but they are not as flimsy as the aftermarket units.

 

Why it makes sense for the fan to always spin. Your engine needs to get rid of excess heat for purposes of optimum fuel delivery and detonation, lubrication and component materials durability. The engine has four ways of doing that: water circulation through the radiator, oil circulation through the pan and filter, and radiation throught the block into the engine compartment, and putting exhaust gases out of the engine compartment throght the exhaust system. When the fan runs all the time, even when the air is cold and the revs are low, it's moving cooler air into the engine compartment and heat out of it so all the ways above work better.

 

I asked a mechanic several years ago the same question about a clutch fan in a 73' Monte Carlo. His answer was the clutch fan has a mercury controlled pressure disk. As the air temp moving past the mercury increases the mercury expands. This in turn causes the fan to increase its rpms. Try torque1st's idea of putting cardboard in front of the radiator after the engine warms up the fan speed will continue to increase until it reaches a 1/1 with the rpm of the fan pulley.

Warning:: Don't try to hold the fan while your wife starts the engine, the friction caused by the spinning disk against the stationary disk has the same effect as hot air passing over the front of the fan - at least that's what a little birdie told me once.