Ok, so I'm having a problem with a squealing belt that I've tried the obvious things without any luck.

I have a 99 Ram 2500 cargo van with 5.9 liter.

It all started with replacing the harmonic balancer. The seal was popping out the side to the point it started rubbing on the metal next to it, causing a burning rubber smell. The entire assembly was rusted over and really hard to get off, so we just replaced it along with the seal. The belt was glazed, so we decided to replace it at the same time.

About 800 miles later, the belt started squealing. No luck on adding belt conditioner. I took it to a mechanic and they said the auto tensioner would be the next most likely problem, or the idler. They took both off and the idler's bearings were a bit tight, so they replaced those. The tensioner's spring and outside was rusted over and didn't seem to be fully functioning properly, so they replaced that too.

I drove off with no squeal. About 10 miles later is squealed a little, then gradually worked its way back to full squeal again.

So I took the old belt and threw it on to eliminate the possibility of a defective new belt. The sound went away for about another 10 miles and then came back again.

It shouldn't be the a/c compressor because the a/c isn't on at all when it makes noise, and doesn't get louder if it's on. I may try bypassing the a/c with the belt just to see, but it doesn't seem likely that's the problem.

I can't find any info on what else it may be so I'm posting in case someone might know what to try next. Any help would be so gratefully appreciated, I'm not wanting to spend more money on another mechanic without getting more info about what's wrong.

Thanks!

 

I've had the belt dressing make more problems in the long run on my V belts.

One trick that has worked for me and others is to dribble some comet or ajax on the belt with the motor running, but perhaps the tensioner's spring is just lacking oomph.

One thing I have also noticed is a weak battery, or an undercharged one can ask for all the alternators output, and since each 25 amps the alternator makes, 1 engine HP is consumed. So just put a charger on the battery overnight and see if there is any difference.

 

It's the belt you're using. Try a different brand.

 

I"m with alloro.. he is sharp when it comes to vehicles.. I put a nicer Gates belt on mine and the squealing went away.

 

i've dealt with this same issue since changing out the RAD, water-pump and the fan clutch assembly. The Duralast (AutoZone brand) belt is a squealer. The CRC belt dressing actually quieted it down for a few miles, but the squeal came back even worse. So, I went the other way, I used some lithium GL-2 multipurpose grease on the outside of the belt. It took 8 applications plus when the temps got hotter out, the squealing went away. The colder it got, the louder it was.

Since the temps here hit 96 and I had done a long road trip of 800 miles, the squeal is no gone, even in cooler weather.

As for another belt brand, yes, it would be better than the Duralast indeed.

 

Ok so I've gone and gotten my battery and alternator tested and charged. A full charge on the battery made no difference, and the alternator tested very good. Still squeals.

Next, I pulled off the belt and checked all the pulleys and bearings to make sure they were all good, and they are. I checked alignment and there doesn't seem to be any alignment issues with any of the pulleys or belt placement.

Lastly, I had a friend do some acceleration while I watched for alignment from above and below...and for the first time I could hear where the squealing seems to be coming from. It sounds like it's coming from the harmonic balancer....which is what was replaced to start off this whole problem. It doesn't appear to be off alignment and I can't make out exactly where it's squealing from. So, what are the possibilities for the harmonic balancer to be the cause?? And what exactly would cause it? Or is it just possible that's where the belt is slipping but it's cause is elsewhere, like the belt itself?


A few of you posted you think it's just a bad belt. That's my next try, to buy a new belt......but, what's weird is that I put the old belt back on and it still squealed. The old belt had been on it before changing it without any squealing, so by switching back to the old belt, it shouldn't squeal....right?


And another small piece of info is that the squealing seems to have quieted down a bit, all on its own. Like the last post said, I think it has to do with the summer temperature going up. I also sprayed a little water on it and it got quiet for a few seconds. I read somewhere to do that and if it quiets down, it's most likely an alignment problem. Is this true?

Thanks for the help so far, I'm really stumped on this one. I'm going to go buy a new belt and try that, otherwise I have no more ideas.

 

You may be on to something on the harmonic balancer. The harmonic balancer has a rubber insert between the inner and outer metals. Hot temperatures causes the rubber to expand, cooler temperatures causes the rubber to contract. If the outer side of the balancer turns faster or slower then the inner portion then you will get a squeal there. Since this squealing problem started just after replacement I would suggest replacing it with a new balancer.

On the belt I use a Gates belt on mine and never have had it squeal on me.

 

Ok, I have the same problem, after changing a bad alternator, it started to squeal badly. I’ve thought I checked everything. I replace the alternator 3 times, still no good, replace tensioner and idler, still squeals. Will motor turning, I went under it and spayed wd40 and when I sprayed it on the fan clutch assembly, its stopped. So now im going to buy one, ill let you know….

 

We tried changing belt..all pulleys looked good... we turned air conditioner on and it stop squealing..is there a belt that we can bypass the air conditioner? My air conditioning works great it just making so much noise I have to turn music up not to hear it.

 

Apply STP belt dressing to inside of belt ONLY, sparingly and cautiously while engine is off. Do not spray this stuff (its basically glue) on the alternator pulley, ac/clutch, fan clutch or any other pulleys including the harmonic balancer. There is roughly 12" of clear belt access on the drivers side: spray only the inside of the belt, turn the engine over, spray again, etc until the inside of belt is lightly coated.

Less is more.