Fan clutch noise?

[jeepcoma]

I've been hearing a noise that's been getting progressively more frequent. It started out only audible when I'd rev the engine really high, up to 4k or so. It's a high pitched metallic noise, sort of what a trailer chain being dragged over concrete sounds like. It's been happening at lower and lower RPMs though, and also I've started noticing it when I downshift and drop the clutch somewhat quick, which causes a quick change in RPM. Thought it might have been the belt slipping briefly but it's a new belt and tension is good, no visible cracks or pulley misalignment. With the hood up, I can rev the engine and hear the noise and it seems like it's coming from the fan clutch (don't have a shroud so don't want to stick my head too close), but my temps are perfect and I haven't had any overheating issues (new aluminium radiator helps I'm sure). I've been reading about fan clutch failures and the result is usually overheating, no mention of noises. Once it cools off I'll try the "spin-the-fan-by-hand" method and check if it's obviously bad. Could this be the fan clutch or should I keep looking? What are some replacement clutch options? If I need to replace it I'd be thinking of swapping to an electric fan since I can probably get a nice used shrouded dual fan for about the same price as a new fan clutch (a quick search showed $60!), and it will help power and fuel a bit.

 

Also, reading through the forums, I've noticed a lot of people taking about an auxiliary electric fan; was that only with A/C? I have only the mechanical clutch driven fan.

[Geonovast]

The factory aux fan, IIRC, was used in the AC models and towing package models.

 

You should be able to drop one right in though, I think the plug might be there..

 

If you're going with a replacement, it would probably be a good idea to go dual electrics.

[Dave Stark]

Mine is going out as well; however its making more of a howling noise. How is it running? Could be timing chain slop...

[dasbulliwagen]

Try removing the fan and keep the pulley in place and see if the noise goes away.

[jeepcoma]

It's running great, I did think of both timing chain slop and maybe transfer case chain hitting the housing... same noise in neutral eliminates the Tcase, and it doesn't really sound like timing chain. And if it were the timing chain, does it make sense that the RPM at which the noise occurs is gradually decreasing? It used to happen only near redline, and now it's slowly worked it's way down to 2.8k or so, and even lower when downshifting. A bad clutch would seem to make more sense there.

 

I will try removing the fan assembly though to see if it goes away. I was watching the fan at idle and it seems to wobble a bit, I'm wondering if a balance issue could be causing premature wear or something else. I also read a tip to remove the clutch spring and it bypasses the low-speed part, so I will give that a try too and see what happens. Also while I was out cooking burgers I tried to move the fan by hand, but it was frozen solid. Engine compartment wasn't quite stone cold, but wasn't exactly warm either. Could I have either a non-thermal clutch or a broken clutch that's always engaged? If the fan is warped AND the clutch is bad, an electric conversion is a definite. I remember reading about a Taurus (I think) dual fan being a perfect fit, I'll have to do some searching.

[dakal]

yes to taurus fan

[offroader461]

i have a Taurus (SHO) fan in my garage...its the ultimate fan...low speed is 2500cfm and the high speed is 4500cfm...was going to put it on the MJ but don't feel like doing it since i spent $30 bucks and got a HD fan clutch instead...The taurus fan is a great swap though