So I changed my belt around a year and a half ago. Had truck in shop in May and while there told mech to look at really bad squeal coming from fan whenever it kicked in high mode. It was quite until fan turned onto high then it sounded like brakes with no pads left. As soon as fan went back down to medium or low, there would be no sound. Mech said he couldn't replicate, go figure. And all pulleys and belt was in order. Back in late July I was inspecting belt and tensioner had bit the dust, completely loose when pulled on. I am getting a chirp now that is directly related to engine rpms. And the metallic sound is still there when fan hits high mode. Any ideas? Squeaky sounds from vehicle are a petpeve of mine.
Used the search tool and there is a couple of threads but not to many people say what really fixed problem.

 

could be you got a bad tensioner out of the box. I had one that chirped and drove me nuts. ordered an oem one and it went away

 

Tensioner is still good, it has plenty of spring in it and has a good belt tension. Anyone know the specs for the correct belt tension. I have a sonic belt tensioner at work I could use to see how far off it is.

Replacement tenaioner I bought was a oem

 

dont know spec for belt but also look at the 2 idler pulleys on the front cover. one has got to be the source of the chirp.

 

Clutch Fan would make this noise, can you RPM to about 2500 does the sound come back?

 

I would have to hook trailer up and get truck temps up or have tech plug computer in and set it. Chirp will increase with rpms. Ear deafening metal sound only happens when fan kicks in high and tries to turn about 2600 rpm according to scan guage.

 

fanss( fan speed)
koeo-0
low-533
high-488
operating values-0 to 4000

 

Don't understand your post?

 

Did you replace the idler pulleys when you did the belt?
It may be time to do that. Also if you like to play with things
the bearings are not that hard to replace in the pulleys.

I just did a quick look in the work book for a tension
# for the amount.

Sean

 

Fan isn't driven by belt, so wouldn't sound be from fan motor if it happens based on FAN speed vs engine rpm?

Sent from my Sprint PC36100 using IB AutoGroup

 

I recently changed the tensioner assembly. But I didn't change the other 2 idlers. I don't have a problem pressing new bearings in and out, but kinda wiry of it since some have said they bent the pulleys when pressing them out. I've pressed countless numbers of bearings in our farm equipment, just that they are usually a lot more rigid.

 

the cooling fan only had low and high on the values , but the fan speed would be what was posted above, just to see where the fan was sitting.
is the truck over heating at all ? maybe take a look at water pump the fins are plastic so I would imagine bearings are crap too, besides pullys .

 

It only happened when I towing heavy load and the temps do get high. If water temp gets up to 220* when towing up hill, fan kicks in high and squeals like crazy, scan guage says rmps are around 2600 or so. Then fan drops down to 1500-1875 rpms and sound will be no more.

At normal driving temps are within 5-9* during summer with a/c on.

 

Sounds like when the fan goes into hi speed, load, the belt is slipping.

 

Maybe a simple cleaning of the pulleys to
remove any grease would help. You may also
want to clean the belt in the process.

Sean