Serpentine Belt Disintegrating

[lozzah666]

Just had heads on VT done up & replaced them ourselves. Engine is running fine, but car has shredded two serpentine belts in quick succession (original & then new replacement).

The belt is disintegrating longitudinally and there is a strange mark along the back of the whole belt where it is tearing. However, we can’t find anything rubbing it there, so maybe it is some sort of flexing or misalignment problem.

We don’t believe that the belt has been installed in the wrong grooves as we took great care installing the second belt (brand new) since we believed that maybe that was what went wrong with the first.

During the head replacement we took the opportunity to replace the bearings in the idler pulleys so that is a highly likely source of the problem – maybe an omitted spacing washer or something creating a misalignment.

We replaced the idler on the tensioner arm with a new plastic unit but installed a large cupped washer that came with it around the wrong way & the washer got bent up. I believe the washer is a protective shield for the idler bearing. Since it didn’t seem to play a role in the actual fixing of the pulley (spacing for instance), & the pulley is fairly cheap and easy to replace anyhow if the bearing fails early, we decided to just leave it off – maybe we misunderstand what the washer does (it’s probably called an ‘Anti Belt-Shred Washer LOL).

We have checked that all the idler pulleys are rotating fine and also the air conditioner pulley, power steering pulley and alternator pulley are all free to rotate OK. All the pulleys look to be in alignment - visually at least. Is there some way of measuring more accurately though.

We believe the belt orientation is right. Grooves are facing inward at the alternator pulley and outward at tensioner pulley. Around the other way wouldn’t make sense anyway.

Another possibility is that maybe we got two of the idler pulleys mixed up (not even sure if this is possible).

They are installed as follows:

1. Small plastic one (with grooves) is installed at idler arm

2. Small metal one (without grooves) is installed at top right of engine (looking from front) displacing the belt run between the air conditioner pulley and the alternator pulley

3. Larger metal one (without grooves) is installed at lower right of engine (looking from front) between the harmonic balancer pulley and the air conditioner pulley to increase the belt-wrap around both of those pulleys.

The only other thing we can think of is that maybe the power steering pump is seizing or overloading the belt. The pump is in a bad state of repair (leaking, noisy, not assisting steering at all) and both times that the car has shredded the belt have been soon after cornering. However, the problems with the power steering pump were pre-existing and so although the pump may be contributing to the problem, I do not believe it is causing it.

Any suggestions anyone?

 

[BOGANV8]

Sounds like the belt is wrong way.. Also in the pic i have and all the vt i have serviced the tensioner pulley should be the NON GROOVED ONE..

The GROOVED one should be top right (between alt and A/C.

Then the one between the A/c & Crank pulley(but up a bit) should be smooth....

Will try and get a diagram for ya. I would say this is why the belt is shredding itself. Also the pulleys have to be spaced in or out as needed so that they are all aligned looking from the side of the car. Otherwise your belts will be running on one edge and shredding

 

[lozzah666]

Thanks BoganV8,

I think that's it. It makes sense that the grooved one goes there - keep the belt running true over the long span. The shredding is probably caused by the smooth back of the belt going over the grooved pulley on the tensioner arm. Surprising how sensitive it is to it - the new belt probably only ran for only an hour max before turning into a fibrous mess.

It's funny, but I could swear the one I took off the tensioner arm in the first place was grooved but I must be mistaken. Shows the danger of leaving it too long to do your re-assembly!

 

[lozzah666]

More trouble

Better, but unfortunately still not the end of my problems.

Have swapped the pulleys, and all seems good - except - the belt is now tracking too far to the front of the tensioner pulley as it tracks over the pulley and this is causing a squeaking noise plus, no doubt, is not good for the pulley or the belt in the longer term.

I really should have paid more attention to this part of the disassembly!

Any ideas anyone? Have I missed a spacer washer beneath the pulley or something?

 

[gav555666]

yeah just went through the same thing with the squeaking whinning noise and found that the tensioner was stuffed,making it "bend" a bit out and not sitting straight. got a new tensioner and is all good now,but the first drive the gearbox died so now the tensioners fixed and car doesnt go anyway.
thats the way(for me) fix one thing and something else will pack it in

 

[lozzah666]

Yeah,

It's like that with cars, a new part moves in and all the rest reckon it's too good for the neighbourhood and go out on strike.

 

[0081]

Seeing as you had it all apart for the heads did you put all the washers and nuts back in the same spot esp the top tensioner as from memory it has alot going on there bolt wise?
this mught be the cause of the belt not running true

 

[BOGANV8]

Better, but unfortunately still not the end of my problems.

Have swapped the pulleys, and all seems good - except - the belt is now tracking too far to the front of the tensioner pulley as it tracks over the pulley and this is causing a squeaking noise plus, no doubt, is not good for the pulley or the belt in the longer term.

I really should have paid more attention to this part of the disassembly!

Any ideas anyone? Have I missed a spacer washer beneath the pulley or something?

I would say you have missed a spacer washer on the tensioner somewhere as the pulley is to close to the motor try undoing it and add a extra washer say 5mm thick & go from there if needs more then take it off & add another till the belt is running true on the pulley

 

[lozzah666]

Some pictures of the problem

OK, I checked around the place but could not find any lost washers so hopefully none missing. In case anyone knows for sure, the pulley on the idler arm just seems to have the one bolt with an integral large washer beneath the bolt head. In any case it seems firmly fixed to the arm with no play.

The problem really seems to be that the idler arm has far too much angular play and this is allowing the arm to swing forward. You can see what I mean in the photo below:

If you look closely at where the arm pivots, you can clearly see that when the arm is under tension it is deflecting badly - gap on left is much larger than gap on right:

With the belt removed, the angular deflection dissappears:

And the pulley alignment seems pretty good (looking along the plane of the belt, you can just make out both sides of the tensioner pulley behind the alternator pulley):

Now, I'm tempted to conclude that I need a new tensioner arm, but before I go shelling out some more loot, is there some way of tightening that sucker up, and also, could it be a problem with how it was re-installed?

Thanks in advance.

 

[BOGANV8]

Just looking at the pic it seems the tensioner is stuffed like you say. I have 2 commo today at work so will look at them and compare the tensioner.. But it would be safe to say that its stuffed cause of the gap you have on one side. In the first pic it doesnt look to good..