Fan Clutch(?) Problem

[RyanVL]

I have a trusty 2002 Ford Explorer XLT V6. Ever since the front end was damaged from an animal strike, I believe this problem started happening. The engine is making that loud "dump truck" roar, especially when accelerating. It's like the fan clutch is fully engaged, no matter what temperature it is outside, even in the middle of winter. This is because of the fan spinning at very high speeds, but I'm unsure if it's the fan clutch itself.

There is no evidence of leaking on the fan clutch or any damage. I am able to move the fan when it's off, not freely or loosely, but it's also not very tight. It feels normal (or from what I've heard, that's normal). Before I move to replace the clutch, I want to be sure that the problem is from the clutch. I appreciate any input.

 

[Gary Crist]

Some fan clutches have a thermal spring in the front of them. It will wear out
and lock up the clutch even cold.

 

[RyanVL]

I see. Definitely a possible explanation for my problem.

 

[Gary Crist]

Eats your gas mileage too.

 

[imp]

's Some fan clutches have a thermal spring in the front of them. It will wear out
and lock up the clutch even cold.

All high-grade fan clutches have an internal valve which controls the angle of impingement of fluid upon internal blades, as well as negative friction coefficient fluid which THICKENS as it gets hotter, thus driving the blades with more force.

Some clutches have an external thermal spring, looks like a tiny clock-spring, which upon changing temperature twists one way or the other to drive a CAM which enters the clutch achieving impingement adjustment. Some utilize a flat-spring appearing device in place of the thermal spring, much like the blade in a household thermostat, to achieve the same thing. These mechanical ideas work in addition to negative friction fluid, which is not nearly as effective alone, and much slower to respond.

Sometimes the fluid leaks out, due to seal failure. Then NO CLUTCH effect happens, the fan spins free, and the engine overheats. Sometimes the clutch bearing SEIZES, causing the fan blade to be driven at high speed constantly, making lots of noise, but cooling the engine all the time. This latter might seem to be the OP's problem, except tightness of rotation of the blade is usually evident upon turning it by hand, which he says is not the case.

So what the hell is happening with the OP's fan? Most likely the thermal spring is damaged, unhooked or otherwise keeping the fluid flowing at proper effect, the internal movable blades are STUCK, or the bearing is dragging enough to drive the blade all the time.
The fix? Replace the clutch with a good, high-quality unit listed for the application. There is a wide variety of specs for clutches, based on application; they are NOT all the same.

 

[RyanVL]

Absolutely. I recently installed a new fan clutch and everything is running perfectly. I was just a little nervous because I wasn't exactly sure if that was the definite problem. Thankfully, it was exactly that.

 

[Gary Crist]

Thank you for your reply! This helps others when they too have a problem!!

 

[imp]

Absolutely. I recently installed a new fan clutch and everything is running perfectly. I was just a little nervous because I wasn't exactly sure if that was the definite problem. Thankfully, it was exactly that.

I would be remiss to not try to help a fellow Chicagoan!

 

[mountaineer2004]

I believe FordTechMakuloco is in Chicagoland now. Real problem solver.