I have a 2005 v5o, and the belt keeps breaking I have replaced the belt a few times. I replaced the tensioner that didn’t work so I took it to the mechanic, he said the alternator was seizing up so he replaced the alternator. Then today it broke again. I don’t know what it could be. Any ideas? The mechanic said the bearing were fine when I took it to replace the alternator. The belt didn’t shred it was like it rubbed off on one side until it snapped.

 

what's on the drive belt? for most cars there's a tensioner, an idler pulley (or two) and then the accessory - ie alternator, compressor, ps pump. All of these should be properly aligned and should spin smoothly with no run out. Sounds like something is misaligned (bent bracket from a prior fail?) or one of the other pulleys or accessories needs to be tested/replaced.

 

I'd use a mechanic's stethoscope on the candidate culprits (same list mt6127 gave above). If you hear anything remotely unusual in any of them, there's a good chance you've found the problem.

Otherwise, I can only think that somehow the belt(s) was(were) damaged during installation - or I suppose by someone messing with you. Or, perhaps it was an el cheapo belt sourced from an unknown supplier in some squalid third-world country that builds belts out of cornstalk fibers. ;-)

 

This is happening to me.
New tensioner, multiple belts.
Indy mechanic repeated.
Went through it again this weekend. Everything including alternator spins freely no bearing noise.

Carefully assembled. Tensioned and ran.
Good for about ten miles then alternator belt is again walking toward engine side shredding one rib at a time.

Is this a known failure point?
It has to be pulley alignment but I can’t see anything amiss.

 

not a typical failure point - unless you have an issue with the AC compressor where the clutch is trying to engage a frozen compressor (ie spins free when testing since the clutch is disengaged, locks up when the clutch engages. Only other scenario I can think of is one of the pulleys isnt properly aligned (say an accessory's bracket is bent or broken)

 

Hey, thank you for response, and sanity check!

This car survived the teens, who definitely took some chunks out of the oil pan, so maybe the shared pulley is “off”.

It’s the Home Depot car, maybe I can delete the ac and fabricate something.

 

So I’m questioning if the right alternator was put on this car, by previous Indy mechanic.
It was infact too far towards the side wall.
I took about a cm of metal off the shoulder on the upper Carrier arm and opened one of the square mounting blocks on the bottom of the alternator. This moved it towards the block appropriately.
I also deleted the stupid air box that blocked access to everything on the top end.

 

wrong aftermarket alternator part would make a lot of sense - partitcularly if the mechanic didnt compare old to new to see if they needed to reuse brackets/pulleys from the original. Sad thing is many times the alternators fail due to the voltage regulator not the bearings/bushings and the VR can be replaced separately on many Volvos (wish VW did this :-(