Squealing/Tensioner shaking?

[239]

A few days ago I started getting a squealing noise coming from under the hood whenever I accelerated on my way to work. Later that day I looked at the belt but it appears fine, no cracks and all of the grooves are still there. I noticed some dry mud on one of the pulleys. I cleaned it off and now the noise only comes back over 35 mph. I noticed that the tensioner is shaking just like in this guy's is: http://www.youtube.com/watch?v=hMtkNE3CASs

I was wondering if I need to replace the tensioner, I'll be removing the belt to run the engine without it and see if it still squeals. I'm pretty sure it's the tensioner though. Also what are your thoughts on belt dressing if it is the belt? I remember we put some on our 98 mounty and it stopped the noise, thanks.

 

[RomeovilleIL]

Belt dressing just makes the belt a little sticky so it gets a better grip on the pullies. The tensioner shaking means the belt is moving over something that is binding while turning. It doesnt guarantee the problem is in the tensioner though it happens often enought. It could just as well be the idler or a/c clutch. Easy test is to take the belt off and turn the pullies by hand. They should turn smoothly with a little resistance. If it can spin freely, binds at any point during the rotation, or has any front/back or side/side play it is shot.

 

[mtnlovrs]

Belt dressing just makes the belt a little sticky so it gets a better grip on the pullies. The tensioner shaking means the belt is moving over something that is binding while turning. It doesnt guarantee the problem is in the tensioner though it happens often enought. It could just as well be the idler or a/c clutch. Easy test is to take the belt off and turn the pullies by hand. They should turn smoothly with a little resistance. If it can spin freely, binds at any point during the rotation, or has any front/back or side/side play it is shot.

Agreed. Also, those idlers are notorious for going bad. The rattling noise in the video sounded much like an idler. I have replaced a few of them on mine and my brother-in-law's Ex's.

 

[239]

Agreed. Also, those idlers are notorious for going bad. The rattling noise in the video sounded much like an idler. I have have replaced a few of them on mine and my brother-in-law's Ex's.

So the idler affects it when it drives too? Is it the shiny one? Sorry I'm kind of a noob, It starts squeaking as soon as it shifts into 3rd gear at 35 mph.

 

[mtnlovrs]

So the idler affects it when it drives too? Is it the shiny one? Sorry I'm kind of a noob, It starts squeaking as soon as it shifts into 3rd gear at 35 mph.

Actually, it doesn't matter whether you're driving or stopped. If the idler is the problem, it will sometimes make more noise at higher RPM's than lower. When mine went bad, they chirped at idle and screamed, squealed or just made a rattling noise at higher RPM's. When the bearings are in real bad shape, the pulley will bind and caused the tensioner to bounce. Sometimes, when the A/C compressor comes on, it will make more noise too. The bearings are a sealed bearing and are packed with grease from the factory. Over time, the seals wear out and the grease leaks out causing the bearing to eventually fail.
On my 5.0 V8, I have two idlers; one is located near the center/upper-front of the engine and the other one is located below the tensioner. I assume yours is similar. Remove the drivebelt and try to rock the pulley (top to bottom). If you can feel any play or hear any noise when you spin it, then the bearing is bad. The bolt in the center of the idler fastens it to the bracket. There is a toothed washer on the back side that keeps the bolt from coming out, so the idler moves away from the bracket as you unthread the bolt. You can replace just the bearing or the pulley with a new bearing already installed. The bearing needs to be pressed in/out, but you can do it with a bearing driver in your garage if you don't have a press. Just be careful not to damage the seal if you use that method.
By the way, other things that can cause your tensioner to bounce are loose pulleys and bad bearings in other components. Grab a hold of your crankshaft, power steering, alternator and water pump pulleys and feel for play in the same rocking motion as I described earlier - (with the drive belt removed, of course). If you don't find any play in your idlers, then the problem may lie in one of these.

 

[239]

Actually, it doesn't matter whether you're driving or stopped. If the idler is the problem, it will sometimes make more noise at higher RPM's than lower. When mine went bad, they chirped at idle and screamed, squealed or just made a rattling noise at higher RPM's. When the bearings are in real bad shape, the pulley will bind and caused the tensioner to bounce. Sometimes, when the A/C compressor comes on, it will make more noise too. The bearings are a sealed bearing and are packed with grease from the factory. Over time, the seals wear out and the grease leaks out causing the bearing to eventually fail.
On my 5.0 V8, I have two idlers; one is located near the center/upper-front of the engine and the other one is located below the tensioner. I assume yours is similar. Remove the drivebelt and try to rock the pulley (top to bottom). If you can feel any play or hear any noise when you spin it, then the bearing is bad. The bolt in the center of the idler fastens it to the bracket. There is a toothed washer on the back side that keeps the bolt from coming out, so the idler moves away from the bracket as you unthread the bolt. You can replace just the bearing or the pulley with a new bearing already installed. The bearing needs to be pressed in/out, but you can do it with a bearing driver in your garage if you don't have a press. Just be careful not to damage the seal if you use that method.
By the way, other things that can cause your tensioner to bounce are loose pulleys and bad bearings in other components. Grab a hold of your crankshaft, power steering, alternator and water pump pulleys and feel for play in the same rocking motion as I described earlier - (with the drive belt removed, of course). If you don't find any play in your idlers, then the problem may lie in one of these.

Well I sprayed the belt with CRC belt conditioner and at first it sounded horrible and I was worried I messed it up even more because everywhere I looked online it said to never spray serpentine belts with anything. It still squealed at exactly 35 mph for a few hours after I sprayed but now the sound is completely gone. Guess it was just the belt slipping at higher RPM's, or has the idler pulley noise been known to disappear then come back?

 

[ejscarfo]

Both the tensioner and idler pulleys went on my 96 5.0 a few months ago. Made the squealing noise at all RPM's. I had bypassed the a/c compressor and noticed that the space between the water pump and upper idler was becoming smaller and smaller and eventually the belt started to rub on itself. I initially thought the belt had over stretched. A new belt did not do the trick and I realized the idler and the tensioner had gone south when they didn't spin freely with the belt off.

It took a half hour to replace both and now the belt is nice and quiet and the space between the 2 pulleys is sufficient for it not to rub.

 

[mtnlovrs]

Well I sprayed the belt with CRC belt conditioner and at first it sounded horrible and I was worried I messed it up even more because everywhere I looked online it said to never spray serpentine belts with anything. It still squealed at exactly 35 mph for a few hours after I sprayed but now the sound is completely gone. Guess it was just the belt slipping at higher RPM's, or has the idler pulley noise been known to disappear then come back?

I suppose it's possible... Is the tensioner still bouncing?:scratch: