Very Loud fan sound

[SBJ420]

Took the truck into the woods 2 days ago, worked out fine, but last two days especially in the morning my truck makes a loud sound from the front. Its hard to describe. To me it sounds like the fan is going 100 times faster than it should and it only does it when I give it gas. truck seems to be running fine, does not drop out or shake or anything. Just the sound. Any ideas?

 

[collegeexplorer]

Mine has been doing the same thing. It happened to mine after 4-wheeling too. Did you go through a lot of mud? You could just need to clean your radiator off really well. For me the mud packs in and locked up my fan clutch, so the clutch wasn't slipping as the engine sped up. I have replaced mine and it got better, but I am not happy with the preformance of the clutch I got from Autozone, so I will be replacing it again this weekend with one from Advance Auto. Hopefully that helped.

 

[snocross1985]

Is it a humming type of noise? That would be the IAC if it is.

 

[SBJ420]

How would I check to see if it was the clutch fan? I did not go through much mud at all, if any. also what is a IAC?

 

[snocross1985]

IAC = Idle Air Controller. It controlls how much air your truck takes in at idle, and only at idle.

 

[collegeexplorer]

I also had my IAC start acting up at the same time as the clutch. Lots of info on here about that and it is a very easy fix if that is the problem. As far as a quick check to see if it is the fan clutch, have someone start your car with the engine cold, and then continue to rev the engine. After about 10 sec, the fan should stay spinning at about the same speed no matter what the engine speed is. If it completly changes with the engine rpm, it might be locked up. You can also check by spinning the fan while the engine is cold with you hand (*engine off*). Then let the engine warm up, shut it off and do it again. There should be a big diference in how easily the fan spins. Also, grab the fan and try to rock it back and forth, and side to side. If it moves much, the clutch is prolly bad.

 

[SBJ420]

okay I am going to check that out. I tryed the moving it with you hand yesterday, it does not move at all when its hot or cold. well it does a little bit but its quite hard. But it deffently speeds up when I give it gas. Seems to do this all day long.
thanks for the info guys

 

[collegeexplorer]

It sounds to me like your fan clutch is locked up, but I could be wrong, I'm not the most knowledgeable person around here. If it is they are about $55-65 at most parts stores. Just make sure you loan the right tools to change it. They save a lot of time.

 

[ma96782]

Fan Clutch...............when cold (engine off) try spinning the fan....it will spin freely or with a little resistance. If it won't spin....replace.

When hot (engine off) try spinning the fan....it will be like there is syrup/glue holding it back. Tougher to spin, than when it was cold. If so, It's OK. If, it spins like a top.....replace.

Aloha, Mark