(I'm new to the diesel world,) the drive belt is very loud and annoying..I went to a local parts store to get a new belt and the guy stopped me from buying it and said it might not be the belt. He told me to take the belt off, turn each pulley and the one that spins "rough" is the one causing the squeal. I somewhat believe him, but I also have some black residue that wipes away that's thrown on the underside of the hood and all around near the belt. I would like to get this fixed tomorrow so I am able to hear the oh so sweet sound of the Cummins! Any help would be greatly appreciated! Thanks in advance
https://www.dieselbombers.com/attach...1&d=1276911724
https://www.dieselbombers.com/attach...1&d=1276911724

 

Does the belt have cracks on the rib side? Is it a dayco belt If you replace it,go with a gator back belt.First clean all the pulleys off with brake clean.Second see if you can see if there is a leak.Have you emptyed your blow by bottle?(black bottle right side as your facing the engine,oil does collect in there over time,this should be emptyed every oil change.)

 

Is that oil or from the belt?

Check the idler pulley.

And yeah, if youre buying a new belt - go for a Goodyear Gatorback or a Gates.

 

and look at your belt tensioner make sure its alright

 

Yeah, I was thinking belt tensioner - but for some reason it came out as idler pulley...