Dad's 04.5 has had an annoying sqealing serpentine belt for the last 5 or 6 months. He had a leak on the front gearcase that was getting oil on the belt and causing it to sqeal. After fixing that the belt still sqealed like crazy and was in great shape yet. Today I put some belt conditioner on it and it made it worse...

An old mechanic friend of mine once told me that brake fluid will quiet the worst belts down. I figured it was worth a shot, and just a dozen drops of brake fluid on the belt did the trick and the thing is quiet as a mouse!

Moral of the story: If your belt is in good shape but is squealing, hit it with some brake fluid... as you all know these belts aren't cheap!

 

V-Belts yes, but on Serpentine Belts I've always heard it's a no-no. I don't know the reasoning.

 

On v-belts, some bar soap while running quiets them down too.

 

Replace it. My 04.5 is on its THIRD belt with only 45,000 miles. As some of the older members here will remember, some of us with 04.5s and early 05s had belts that shredded for no reason (my 1st went at 5400 miles). 2nd was wearing poorly after 30,000 miles, and I had the overruning pulley TSB performed and another belt put on. Knock wood, this 3rd one has been okay so far.

 

If that truck still has the original belt tensioner, now would be a good time to replace it.

 

What's the over-running pulley TSB about?

His first one wore out around 70K, his last one shredded at around 50K, this one only has about 20K on it. It still looks good, and all the pulley bearings are still tight. I'm thinking the oil bath it took just hardened it up a bit, but the brake fluid seems to have softened it up.

 

It takes of the squeaking noise you get on shutdown from the alternator pulley. You can read about it Here.

 

It also eliminates the stress on the belt at shutdown, which, in my opinion, contributed to the premature wear on the belts.

 

I'm on my second belt at 40k. Good for the belt or not I enjoy that I6 shaking the truck when it shuts down!