Serpiente belt squeak

[Firemn260]

So after I did all the timing chains and cassettes on my 2003 it is running great. I just got back from a 1250 mile round trip run to the Smokey mountains in Tennessee. I love this truck.
Right before I left I replace the belt, idler and tensioner pulley because it was making noise. It was all quiet until about a week ago and the squeak came back. I’m not talking about a chirp, it’s a loud constant noise that’s annoying the crap out of me. All the pulleys look to be in alinement and when I sprayed some water on it it goes away for a moment so that ruled out any bearings. It seems once the truck runs for a while it goes away but now that it’s getting colder it seems to last longer before it does.

I replace the belt with a Dayton and I’m wondering if it maybe is the wrong size?
Any of you run into this problem?

 

[Jazzer]

Dayton’s generally good, but you might try putting the old one back on and see if the noise changes. Use a good straightedge on the pulleys- eyeballing it isn’t really precise.

 

[SenorNoob]

I noticed awhile back that all of O'Reilly's belts are 1/2 sizes. Most of the time it's fine. but sometimes a 1/2 in more longer will squeal or a 1/2 in shorter won't go on. All depends on the original setup. I had problems when I changed to a 130 amp alternator and the pulley size was like 3mm different.

Also you replaced tensioner pulley but what about the tensioner itself? They do wear out.

 

[Firemn260]

I noticed awhile back that all of O'Reilly's belts are 1/2 sizes. Most of the time it's fine. but sometimes a 1/2 in more longer will squeal or a 1/2 in shorter won't go on. All depends on the original setup. I had problems when I changed to a 130 amp alternator and the pulley size was like 3mm different.

Also you replaced tensioner pulley but what about the tensioner itself? They do wear out.

I replaced the whole tensioner.
It seems it goes away once the belt warms up so I was thinking it may be to tight.
I thought about trying a motorcraft belt from ford and see if that makes a difference.
I had read about trying a v belt from continental but I can’t seem to find one anywhere.

 

[SenorNoob]

I've never heard of too tight causing noise until it caused a bearing to fail... But I suppose it's possible.

 

[Broosedamoose]

I have the same issue! It started to chirp then got worse so I replaced the belt (it was showing signs of age anyway). It continued to chirp, so I replaced the tentioner and idler pulley. Still chirping. Took it down to my mechanic and he tried the water trick and the chip went away. He said the tentioner looked to have a lot of room left to compress and that the belt might be too big. So, I got another one a size smaller. The chirp went away for a few days but came back. It only seems to do it when I first start her up and whenever it's raining or damp outside. I still haven't figured it out. My mechanic said it could be the harmonic balancer and is going to check it with a straight edge. I just haven't had the time when he has the time.