Serpentine belt appears to be giving off shavings

[69GTX]

I've never seen this before on any of my cars. Either a belt cracks or breaks, but I don't ever recall one being shaved down such that little rubber flecks are being strewn over a fairly wide area.

I think it's coming from the belt as it rides under the belt idler pulley on my 4.6L. The most shavings are directly below and above that pulley. Those bits also ride the belt and end up elsewhere such as the face of the alternator or on the inner fender ledge...or at any point along the belt travel path. My best guess is that it's the edge(s) of the belt that must be rubbing somewhere or getting overheated near the engine somewhere. I don't see any direct contact from above though. Both edges of the belt do look a bit rough and crusty. A 1/4" pile of shavings accumulated under the BI Pulley. The BI Pulley has some shiny worn spots on the surfaces that I don't recall seeing before. After tonight's 10 mile ride (in 32 deg F weather) I checked the belt and it was cool to the touch.

I don't recall seeing this problem back in August so it's probably fairly new. My local shop replaced the radiator at that time, though I don't see where they would have done anything to the belt/pulleys. Will continue to monitor it every couple days. They're supposed to be replaced at 100K miles. At 68K mine is not cracked or brittle.

Anyone seen a belt shedding rubber like this before?

 

[clinebarger]

On a 13 year old car, The drive belt will need changing, The belt is likely hardened/glazing. Check all accessory drives/tensioner pulleys/idler pulleys while the belt is off.

 

[69GTX]

Originally Posted By: clinebarger
On a 13 year old car, The drive belt will need changing, The belt is likely hardened/glazing. Check all accessory drives/tensioner pulleys/idler pulleys while the belt is off.


Thanks. Probably the case. The original belt on my 17 year old car is nearly perfect and as flexible as can be. I can still see the belt fibers on the edges...which I can't see on the other car as those are like ragged mush.

I also have some 20-22 year old V belts that came off cars I had in the early 1990's. Most of those are still in nice shape. I did check the two 45 year old belts I have that came off original 40K-55K mile 1969's. Those are a bit ragged.

 

[oldhp]

Check the idler bearing, it's probably bad letting the pulley run crooked under load.

 

[DoubleWasp]

Crooked loading, dragging accessory, or fluid leaking onto belt.

 

[Merkava_4]

Originally Posted By: 69GTX
Anyone seen a belt shedding rubber like this before?


Yes, when people apply belt dressing to a serpentine belt. Belt dressing is supposed to be for V-belts.

 

[BlackBeard]

I have this same exact problem. Let me know what you find!

 

[Lubener]

Originally Posted By: oldhp
Check the idler bearing, it's probably bad letting the pulley run crooked under load.


Go one step further, look for a powdery rust near pulley bearings. That will confirm a bad bearing. I have also had to shim components to get proper alignment of all pulleys.

 

[SwampSurvivor]

I think it's just an old belt.

Or, according to this guy, it's ethanol in the gas ...
https://www.youtube.com/watch?v=F7LDnwsPpoc

 

[The_Eric]

Take the belt off and give all the pulleys a spin. Pay special attention to the idler pulley, the tensioner and alternator. They should all spin very easily and make no noise.

 

[SteveSRT8]

^^^This. Then get out your straight edge and verify alignment.

After that the individual pulleys must be inspected for damage...

 

[69GTX]

Originally Posted By: DoubleWasp
Crooked loading, dragging accessory, or fluid leaking onto belt.


Thanks for all the tips. There is a tiny fluid leak somewhere deep down on that side. It could be power steering, valve cover, etc. Doesn't make it to the ground but it's on the hoses and frame. When the car was in for the radiator change my mechanic of 30 years didn't think it was much of a concern. Now, will probably have to look a bit deeper into the passenger side of the engine where everything is crammed in on the 4.6L.

 

[69GTX]

Another look at it and I can agree with the "glazing" comment too. The belt feels somewhat soft on the reverse side/flat surface. Seems a touch "tacky" liked you'd expect a slick to be prior to a drag race.

Over the past 1-2 months or so the car has seen some higher RPM operation (3,000-4,000 in 1st-2nd-3rd) more than any time in the previous 5 years. Could those higher rpms have created some extra friction/heat in this older belt to start to break it down quicker?

 

[The_Eric]

Take it off and inspect the bearings and pulleys. Belts do not just start shedding rubber for no reason.

 

[artificialist]

Carefully examine the harmonic balancer. Remove the belt and run the engine.

Sometimes I see bits of metal near the pulley as it is failing.