Idler pulley or tensioner?

[JMA1181]

I have a squeling noise coming out from under the hood. My cousin says it is an idler pulley that cost $20. He says it is not the tensioner because the belt still has tension on it. He determined which pulley it is by spraying wd40 on one of them and the squek didn't go away. He then sprayed it on another one and it went away immediately. Once he quit spraying on that pulley the noise came back so he said that pulley was the problem, does this sound right? He also said he is going to have to take the plastic off from around the fan and start removing stuff from the front of the truck until he can get to it. What are the options as far as this goes? He is going to replace that pulley and the belt. Any advice would be greatly appreciated!!
Thanks, Jordan

[greasltn]

Which belt is he replacing? There are 2 belts. Does he know these trucks, or does he just think he can handle it?

[JMA1181]

He works on cars and trucks all day long and looked at it the other day and said he can do it. I don't know that he has much experience with diesels though

[Benwood]

I dont know about the pulley on the tensioner, but ive replaced that tensioner twice, not too bad from the bottom dont have to take anything else off, putting the belt back on is exponentially harder than replacing the tensioner, especially by yourself

[Big Angry Hillbilly]

Better order an upper fan shroud and fan stator, if he's never worked on one before.

Tensioners are problematic on these engines, FWIW.

[JMA1181]

Well we ordered 2 pulleys and one of them was the incorrect one so we only replaced one. Didn't take care of the squeek so we are sending back the wrong one and putting a new on on tomorrow. He was able to replace the pulley fairly easily and he says the tensioner is not bad. However, when the intercooler pipe was taken off there is a substance in there. It almost looks like grease with some water on it. We figured the water was from condensation but where is this grease like stuff coming from? The coolant level has not changed and the oil appears to be fine.

[forddieseldoctor]

That's normal. I see it on everyone that I remove.