Serpentine belt damage AGAIN!

[Glutton4punishment]

First off I would like to thank you for all of your input on the forum.
I understand how frustrating something like this can be. I don't know about your car but my E89 is a bitch to change the serpentine belt on plus those belts aren't cheap. As much as I hope this discovery and replacement helps I just can't imagine why it would make a difference to the belt. I only say this based on most cars manufactured do not have a one-way freewheeling pulley on them. They for the most part are simply a keyed pulley. When replacing did you find worn out bearing or something that would allow the pully to run out of alignment?

 

[matreyia]

First off I would like to thank you for all of your input on the forum.
I understand how frustrating something like this can be. I don't know about your car but my E89 is a bitch to change the serpentine belt on plus those belts aren't cheap. As much as I hope this discovery and replacement helps I just can't imagine why it would make a difference to the belt. I only say this based on most cars manufactured do not have a one-way freewheeling pulley on them. They for the most part are simply a keyed pulley. When replacing did you find worn out bearing or something that would allow the pully to run out of alignment?

The issue is not alignment. It is the stress from the locked malfunctioning decoupling mechanism. It shears longitudinally on the belt and tears. The car is now smooth idling less vibration.

 

[fmorelli]

And motor mount happiness? Crazy how something stupid like this sends us on a goose chase :-(

Glad you found it.

Filippo

 

[Glutton4punishment]

I really do hope this turns out to solve your problem. But the stresses of the resistance of the alternator would not pull the belt apart longitudinally. Yes I do agree the freewheeling action could help with idle smoothness. The rotational mass of the alternator is allowed to continue even if the motor rotation slows for a split second. I can see this would help smooth out idle.
You have mentioned replacing all pulleys at one time or another. This is a long shot but could one of those pulleys have a different number of groves. Or could the spacing between grooves be slightly different? I believe something has to be pulling the belt apart and or compressing it together repeatedly to split the belt like that. But again I have my fingers crossed that you have found your problem. But if it comes back and again I hope it doesn’t you may want to consider groove spacing.

 

[matreyia]

I really do hope this turns out to solve your problem. But the stresses of the resistance of the alternator would not pull the belt apart longitudinally. Yes I do agree the freewheeling action could help with idle smoothness. The rotational mass of the alternator is allowed to continue even if the motor rotation slows for a split second. I can see this would help smooth out idle.
You have mentioned replacing all pulleys at one time or another. This is a long shot but could one of those pulleys have a different number of groves. Or could the spacing between grooves be slightly different? I believe something has to be pulling the belt apart and or compressing it together repeatedly to split the belt like that. But again I have my fingers crossed that you have found your problem. But if it comes back and again I hope it doesn’t you may want to consider groove spacing.

Incorrect number of groove would be an impossibility since that changes the width of the pulley and would cause belt to not fit. On e9x series, there are two part numbers that have different groove numbers so be advised ifnyou need to replace the alternator pulley. fcp euro sent the wrong part initially and i just got the correct part yesterday and installed it.

In the photo, the old black pulley has more grooves than the FCP euro wrong pulley.

 

[matreyia]

And motor mount happiness? Crazy how something stupid like this sends us on a goose chase :-(

Glad you found it.

Filippo

As for the motor mount, I am going to replace the Black Forest Stage 1 mount with a second stock 335iS mount and be done with it. Even though it is not as crazy as the revshift mount, it is still annoying me enough to bite the bullet.

 

[matreyia]

OK, I can confirm that it WAS the alternator pulley that was tearing the belt longitudally. After replacing the alternator pulley, and going full blast multiple times...zero signs of belt damage anywhere. So: 1. changed power steering pulley due to damaged teeth, and that did not fix the belt damage issue. 2. changed the alternator pulley that had failed decoupling function and that fixed it.

Cheers.

 

[DS3IAM]

I didn't read everyone's responses but did anyone suggest AC pulley? Unfortunately, for me my AC pulley failed and it had the similar look to the belt in question. It was only damage on the edge of the belt itself.

Glad you found the issue!

 

[matreyia]

I didn't read everyone's responses but did anyone suggest AC pulley? Unfortunately, for me my AC pulley failed and it had the similar look to the belt in question. It was only damage on the edge of the belt itself.

Glad you found the issue!

Nobody suggested the AC pulley. It was only after a last ditch effort Youtube search about noises and damage to belts that I finally tried to test my alternator pulley like the videos suggested. And indeed the pulley was totally stuck with no functionality to decouple.

 

[matreyia]

Ok, I have held off final results but I think it is long enough now that I can definitely make a proper call. So my belt once again cracked along the longitudal and I double checked my new replacement üro metal pulley and it was fine, checked the alternator pulley just replaced and it still works normal...but when I checked the main center harmonic balancer there were crusted baked in hardened gunk that filled in the same regions that matched the tear along the belt. I took a scraper and some liquid wrench and scraped it all off and replaced the serpentine belt again... and so far zero damage after a couple of months of hard driving. Previously the belt would get the damage after one month of driving normal.

So if you are getting longitudal cracks along your belts, then make sure the teeth grooves of all your pulleys are clean of foreign gunk that may have filled in the grooves in some parts.

 

[fmorelli]

Any idea what actually got in there? That whole area is pretty covered up.

Filippo

 

[matreyia]

Any idea what actually got in there? That whole area is pretty covered up.

Filippo

Looked like mud and dirt that calcified over time. was pretty bad, almost covered part of the grooves.