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Squealing serpentine belt

23K views 30 replies 14 participants last post by  The Lox 
#1 ·
Hey everyone, My serpentine belt all of a sudden started making a very loud squeal that goes up and down with engine speeds. I can spray on belt dressing and it only stops for a couple seconds and comes back.

I took the belt off and it does have lots of small cracks in it. I will change that and see if it helps.

I took the belt off and turned all pulleys by hand and they feels smooth except the power steering, but that may be normal. Anyone know for sure if it would have a "bumpy" type feeling when you turn it by hand? Not bumpy like out of round, just not a smooth feeling when the pulley is turned.

My Bronco has also has a very dry sounding friction sound when it get very cold. Like a dry bearing when it gets below 20 degrees. Doesn't do it when it is warmer out.

I saw a few years back where someone posted the bearing numbers for the idler and tensioner pulleys. I wouldn't mind changing them out myself to save a few bucks. Anyone know the bearing numbers?
 
#2 ·
thats normal im sure. replace rethe belt. it never hurts to. if its not the belt it. its alot easier to prelac ethe whole pully than try and repalce the bearings i would assume. theres a good chance ur smog pump can ause noises also
 
#4 ·
A new belt made all the difference in the world.

I do need to change the idler and tensioner pully. At least see if it still makes that dry bearing noise this winter.

The idler pully looks like about a $20 part, easy enough to just get the new part. But the tensioner looks like a $50 part. I may have to see how easily the bearing can be changed out in that one. Anyone know the bearing part # for that one?
 
#5 ·
Defiantly check out the idler pulley. There is a lot of tension on the plastic pulley. The bearing insert might be starting to spin inside the pulley. Mine disintegrated at 60 mph. I carry a spare now as it started squeaking again. Just so you know, I'd bet a paycheck that on that "belt dressing" can, that it says "Not for use on serpentine belts" ;)

KC
 
#11 ·
Mine just started to make a really loud squeak as the rpm's increase a few days ago. I replaced the belt tensioner and the stock bracket it attaches to so they are good. I pulled the Motorcraft serp off last night and had my wife rev it, doesn't squeak at idle, and as she rev'd it there was no noise. Which is good because I though it was inside the motor. Now I just have to rule out a/c, p/s, and idler pulley. The pump is a new Sag and the idler has been replaced but not in a while. I pulled it last night too and saw that insert you are talking about but it threaded on okay, went in the bearing snugly, and the bearing felt smooth. Had a little leak from one of my duel return fittings on the Sag that was capped off pending hydro-boost in the future, so I replaced the cap with a piece of trans line and a brass fitting. Then I cleaned off the p/s pulley but maybe a Gatorback will help? Who stocks those?? Anyone know if it harms a new a/c compressor, filled with oil, if you don't have the system charged? The clutch spins without engaging so it seems like it is just "free spinning" and not binding since the power isn't hooked up. Could the Sag possibly having fluid slightly in the groves cause it to "High Pitch Squeal" when the motor is slowly rev'd but not at idle? I sprayed some brake clean on all the pulleys and wiped them off and wiped the belt too with some to remove the residual p/s fluid on it but after installing it the squeak was still there when rev'd. :thumbup -Kevin-
 
#6 ·
belt dressing is a temporarly fix. that and the fan makes it spray black crap all over everything.

i think that the idler and tenshioner use the same pully. what you saw for 50$ was probably the whole spring assembly inclueded. i could be wrong tho
 
#7 ·
I replaced my tensioner in a quest to get mine to stop making noise, and it did absolutely nothing. As far as the belt goes, I found that after replacing mine 3 times with cheap parts store belts at the time, it squealed like a pig every time no matter the rpm, and the last one left me stranded. I ended up buying a goodyear gatorback about 2 years ago and that thing wont make a noise unless there is water being sprayed directly on it.
BTW, i work at a parts store and there is a reason there basic belts are usually only warrantied for 1 year:doh0715:
 
#10 ·
Be sure to clean all pulleys with degreaser and a brush. Then apply a new clean belt. Never apply belt dressing. The tensioner and idler pulley do wear over time which necessitates replacement. IMHE, I have found Gates to be a better belt than the Goodyear Gatorback as it is much more robust and reduces squealing issues.
 
#12 ·
Be sure to clean all pulleys with degreaser and a brush. Then apply a new clean belt. Never apply belt dressing. The tensioner does wear over time which necessitates replacement. IMHE, I have found Gates to be a better belt than the Goodyear Gatorback as it is much more robust and reduces squealing issues.
Just a regular Gates? I have always run a Motorcraft and thought Gates were good aftermarket ones but second to Motorcraft. I just thought the Gatorback was suppose to be something special and good for ending squeaks. I can get emp cost on Ford stuff so if Gates (O'reilly Auto) is your choice is it better for this than Motorcraft Seattle? :thumbup -Kevin-
 
#14 ·
I had same problem with my wifes 1994 E350 Clubwagon, 5.8 after looking up belts at NAPA I noticed 2 belt sizes listed for the 5.8. One belt was 1/2 inch longer, (longer belt listed second, and for H/D) changed to longer belt no more squeal.
The shorter belt also killed the bearings in smog pump in about 3 months. Tensioner has a pointer to let you know if belt is tight enough (Ford tensioner makes a difference).
I've had a lot of Ford trucks/vans with the 5.8 squeals. :rolleyes:
 
#16 ·
You know it's funny. I've always used Ford tensioners and belts but never have I seen the pointer other than in pictures here. I don't know if they were only on production model parts because in 9 years I've replaced mine about 4 times and it hasn't been on there?
 
#21 ·
Off hand I'd bet it's a 6203 bearing the 6203 bearing is the most common
ball bearing in the world and so it's cheaper to buy, so it's #1 position is
secure. ;)

"22 long rifles vs. 22 shorts, you get more for less because of production costs" -Alvin

Auto parts stores list 6203's as a 203 bearing. I don't buy 'em there I get
my bearings at a bearing shop (or McMaster-Carr.com) since they charge
like half what the auto parts stores charge for the same quality bearing.

The A/C clutch (that Scuba don't got;) uses a double row bearing = 5106.

Plastic idler/tensioner pulleys that have the plastic molded all around 'em,
I've never figured out a way to replace th 6203 in one of those. That's a
first for this tinkering fool! :)

There's an idler that's an odd ball on my '75 F150, it uses a "water pump
bearing" that includes the shaft and a double row of bearings. :)

--------------------

Paid mechanics don't change out bearings, it's not in their interest to do that.

So most people never even think about fixing something they just replace
the whole "part" the way the mechanic does it.

My '75 F150's still got all it's original stuff like the silly little belt tensioner and
idler pulley plus all the other stuff like the power steering pump, alternator,
starter, A/C clutch, A/C compressor, steering column, drive shaft, 360FE xD,
T18, rear axle housing with its original Ford9inch too.

All that stuff's had their bearings replaced.
No big deal. :)

Alvin in AZ
 
#22 ·
I just put a new bracket on because my belt tensioner bolt stripped and the heli-coil didn't hold too long. I put a new tensioner, bracket, and now a new belt because it kept squealing. I finally searched down the squeak with a rubber hose and it was the spring on the tensioner rubbing on the bracket. I wrapped the pulley and belt with clean towels and lightly and quickly sprayed a "little blast" of lube spray on the spring. Noise disappeared and hasn't come back! Of course this was after removing the tensioner 3 times, torquing to specs twice, and generally beating my head to death trying to figure out where it was coming from. Couldn't be the tensioner because I just replaced everything, right? WRONG! :banghead:banghead:banghead....:thumbup -Kevin-
 
#23 ·
I just fixed my noisy belt. It was old and cracking and my tensioner pulley was shot. Bought a new motorcraft pulley for it and Gatorback belt. Drove it all weekend in the pouring rain and there is no noise at all. I will let you guys know if it starts to make noise again.
 
#27 ·
you should always replace the tensioner as a whole unit

even though you can replace the pulley/bearing you are only
wasting time and money

the pivot on the tensioner wears out and loses its alignment
thus misaligning the belt causing premature wear and squealing
Good point about the wear it -could-have- but leave out the "gotta's" Ok?
...because there -is- such a thing as checking your-own for wear.

But really good point about the wear tho, check yours for wear before
messing with the 6203 bearing? :)

2 out of 3 of mine are in top shape. YMMV

Alvin in AZ
 
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