Afox570

I have a 2000 xj. 4.0. Im new to this forum thing but ill try it out. Im pretty mechanically inclined but for some reason this has me and a few other older mechanics i know stumped. My xj radiator fan is always on. The fan clutch. Not the electric fan. I went and bought a new one. Still does it. From the second i start it till i park it. Sounds like a plane lol. No overheating issues. No bad readings. Its on an idler pulley. Could that be causing it? Cause i thought the idler pulley is free spinning. No bearings or anything. But thats why im here asking. Any help? Not causing any issues other then the amount of power i lose when going up in rpms.

tech

A good fan clutch when new will make noise all the time , as it brakes in it will get quieter .

PatHenry

There is definitely a bearing in that bracket for the fan clutch. It's not easily serviceable though. The easiest thing might be to figure out which Jeep years are compatible and get the assembly from the junkyard, or a competent machine shop that specializes in bearings and the such can probably rebuild it.

Hopefully your bearing isn't bad and it's just the fan clutch breaking in as previously mentioned. FWIW, my fan spins like that as well. I'm assuming it's sort of just the rotational force making an easily spun fan spin, but it can slip easily so it's less force or lower RPM than when the clutch engages and locks the fan in sync with the belt speed.

Afox570

Thanks for the fast replies guys. I guess ill see as it goes and see if it breaks in. Like i said. Theres no issues with it really so im not to concerned. I just hate how loud it is and the loss of power from dead stop. And there is a bearing? On the pulley?

tech

You did get a fan clutch for a xj and not the one for a grand cherokee ?

Afox570

Xj. I make sure i get the right stuff. Ocd about things lol.

gat

How does it sound when you spin it by hand without the belt in place? You can use a stethoscope or a long, solid screw driver to listen to the bearing.

dale500

The fan blade is going to spin all the time, even from a cold start. The clutch isn't designed to freewheel when cold, just to spin the fan at a slower speed to help the engine reach operating temp. It will continue to spin faster as the engine heats up and the clutch locks up.

PatHenry

The bearing is in the bracket. It's pretty rare for it to fail, but it does happen. There are many threads on multiple forums about it. The typical solution is to go to a junkyard and get the whole bracket. I'm sure a shop that specializes in bearings can replace it, but since you're pulling your bracket off either way, the deciding factor seems to be the difference between $20-$50 at a junkyard vs. a couple hundred from a specialty shop.

Whether the bearing has failed or not wouldn't have anything to do with whether the fan spins or not, it would just make the chirping/squealing/grinding sound (and eventually possibly seize up) or not. The airplane sound is entirely due to the fan itself.

PatHenry

Don't a lot of folks actually choose to run a particular GC clutch as an "upgrade" or am I not remembering correctly?

Ralph77

That is what I heard too. When I decided to do my fan clutch, I watched that video that showed how a good one is supposed to operate and how a bad one does too, I toyed with the idea of using the GC one. My boss said since you don't tow and don't have any cooling problems don't. Said it will be noisy and might tank the MPG.

IJM

When you say the mechanical fan is always on, do you mean it's always spinning when the engine is running, or do you mean the clutch is always engaged so that the fan will make an obvious roaring sound when you bring up the revs a bit? It's an important distinction since the fan always spins when the engine is running. It'll roar a bit at startup until the fluid in the clutch gets sorted out, but normally when you bring up the revs with a cool engine the fan won't really spin any faster. Here's an example of what the fan is supposed to do when the clutch is engaged when hot.

tech

Yes some use a fan clutch from a grand cherokee as a up grade , most say it very loud all the time but it does help keep the xj cool .