Help! question about drive belt!



(Reposting, I need a quick reply. Don’t mean to spam…)

I got my timing belt,drive belt water pump replaced by the VW dealership (Winn VW of fremont) in April. Ever since, there has been a different sound (a high frequency hum) in the car. Lately the sound got worse, like a grinding noise and I took it back in. The day I took it in, there was smell of rubber burning too, but only for a little while.

The diagnosis was a blown ac compressor.

They said that the rubber burning was nothing serious and that I could drive it around “safely”. Well I took it out with the intention of trading it in, and after a while I had fumes coming up from the hood. There was a red battery sign in the dashboard and so I pulled over.

The drive belt was burning away and I had the car towed back in the dealership.

This morning they said it was the alternator that caused my drive belt to go bad. Can this be true?

I have a feeling that they did not install the belt properly which cause the ac compressor and the alternator to go bad. Is there a way to prove this one way or the other?


The belt being improperly installed wouldn’t cause this problem. The alternator light is probably coming on due to the belt failing or not spinning the pulley correctly. If I had to guess, I’d guess the real problem is a bad belt tensioner, and that when you brought it in perhaps they noticed a bad AC compressor and assumed it to be what was causing the belt to not move properly.

Or it could just be you’re having bad luck and the alternator just went right after the AC compressor.

Was your AC working?


Since it just happened, they probably messed something up while doing the work.


I tried turning it on for a few minutes time and again since it was so hot. It seemed to be blowing some amount of cold air, but wasn’t running very cold.
There was a rubber burning smell at some point of time after which I turned it off.

Wouldn’t I see some signs of the alternator going bad, like the car not starting up etc? I haven’t heard that an alternator goes bad and chews up the belt like that.

It was a great car before they did that work on the timing belt. I get the feeling I paid them 2400$$ to total my car :frowning:


It’s possible to ovetighten a drive belt that can then cause bearings to fail. Can you be more specific about the failure?


I would tell you the specifics if I knew. All I know is the shop claims that the alternator bearing failed causing the belt to burn. I am fighting with them to fix it because I think its the work they did on it that made it fail like that.


Does your car have an automatic tensioner for the belt? If so, the mechanic would not be at fault. If no automatic tensioner, then an overtightened belt can cause an the alternator bearing to fail. This would not be easy to prove unless you had another mechanic who would agree with this and would acompany you to small claims court if needed to convince your mechanic who did the actual work to make a satisfactory financial adjustment.

We are not talking massive engine or transmission failure with resulting extremely high costs. Your best bet is to eat this and move on and find a better mechanic who will admit to occasional failure or else provide a reasonable and convincing explanation as to what happened that was not his/her fault. You can be sure that all people make occasional errors but some will never admit to any if they can get away with it.


I’ve cranked down pretty hard on belts in the past, often using a crow bar or long breaker bar to really get them tight. I’ve never smoked an alternator or AC bearing yet.



I think I will take up their offer to share the costs with me.


Ok, That is the answer I was looking for. According to my mechanic, the tensioner would have kept the belt from doing something bad to the alternator. I just wanted to hear it from someone else. Thanks.


This happened to me. The A/C compressor bearing seized up.