Sorry for not posting this in the truck forum but not too many people go there so I wanted to post it here.

My 98 Dakota 3.9 litre has developed a bad squeal. I bought a new serpentine belt, made it worse. As soon as I sprayed belt dressing on the belt it got REALLY LOUD! I bought a new alternator and the problem is still there. If I spray WD40 anywhere on the belt the motor is silent.

I'm gonna get a shorter belt to bypass the air conditioner, that will eliminate that. I've done the alternator so bypassing the air conditioner will leave only the crank pulley, fan pulley, and power steering pulley.

I already bought a new tensioner pulley also, and the tensioner arm doesn't squeak when I move it back and forth quickly with a long ratchet.

Any ideas??

Try a Gator Back belt.We had a few that would squeal and either the cheap belts or the Gators stopped it.That and clean that junk off all the pulleys.Dressing wasnt made for serp belts.Rocky

Something's just telling me it's not the belt, but than again spraying WD40 on the belt silences it so maybe it is the belt.

It's probably the tensioner, they lose pressure over time, on everything I've owned with mag motors I've been lucky to get 40k out of one, if the tensioner isn't really stiff the belt will slip.

Only use a mopar belt also, everything else is junk, I've had gates and goodyear belts stretch 2" in a month but I ran my stuff pretty hard too.

Put a little buffing compound or toothpaste on it. That will stop a sqealling belt.

Comet works good for serp belt noise.

Get a new tensioner with pulley. The spring is weak. I went thru the same thing. Mike

sounds like something is trying to lockup. Spraying WD40 is letting the belt slip over what ever pulley is locking up.

My '88 GMC 454 dually had a belt squeal, putting something on it would silence it for awhile but it would come back. Sure enough, it needed a tensioner. 88,000 miles. Replaced the belt for good measure too as it was showing some cracks, and it was about 5 years old with less than 10,000 miles on it.

I vote tensioner, I've put 2 on the my Caravan in 175,000 mi
clean all crap off the belt & pulleys.

I had belt squeal on my 93 RamCharger 5.2 magnum for the longest time. Tried Napa belts, autozone, etc.... all squeaked. Finally went and got a stock Mopar one and it hasn't squeaked yet. I don't know who makes them. But they work


Ryan

Had belt squeel on an 01 Dakota with a 3.9 with the Mopar Belt. Swapped to a Dayco belt and much better.

I don,t know if this helps where your at but I found free,like new, belts at the junkyard. Saved me 60 bucks.

I doubt its the tensioner.My 99 has one that wont spring back.I push it tight and never has a noise.Yeah it still has the OE belt thats 10 years old as is the one in the 96 Concord.Not saying it cant be the tensioner.The 3.3s were known for tensioners in the mini vans.They even have a TSB for them.I do this every day.The Dayco or Gator backs are some of the best Ive ever used.Ive installed thousands.So listen to a guiy that had one once or someone that does it thousands of times a year.Its your money and your choise.Oh cleansen and other junk is just a bandaid.It might be ok for a while but would you pour sand in your belys? I think not and its probally less abrasive than that.Rocky

Well I sprinkled some Comet on the belt and the noise went away.

The tensioner is tight, I have to use a 2 foot long ratchet to move it to remove the belt. I'll get a new belt soon and get it figured out.

with Rocky. I've seen this many times myself. Replace the belt with either a Dayco or a Gatorback. Anything else is a waste of time and money. The fact that the noise goes away with the wd40 proves it's the belt. Been there done that so many times I can't count. I would also check the condition of the pulleys while the belt is off and replace as needed, but the belt is the noise.