S-belt Squealing and Chirping (with video)

Hi Guys,
I've got a situation that has recently arisen on my '96 B4V. My s-belt started slipping and squealing some time ago and got worse and worse. I just replaced the tensioner and belt, and the squealing is actually worse! It only squeals on startup when cold for a few seconds and then over ~3000RPM's. I know it's the s-belt because I lose alternator charge when it starts to squeal.

Also, there is a consistent chirping at idle. It goes away under rev. I have a video here of the chirping and I imagine it's related to the squealing. I'm hoping someone has heard this exact chirping before and knows exactly the problem.

Two notes: 1) I did the updated alternator Gates clutch pulley about 2 years and 30K miles ago and have not tried switching back to the old pulley yet, and 2) I'm pretty sure the car already has the newer style crank pulley.

Thanks!

with everything off for several hours check batt with multimeter, if ok check alt charging. when was the last time you did batt? alt?

I've never done the battery or alternator...they've been in the car since I got it in June 2014 (~50K miles ago). Battery is Napa Legend 7541, June 2013 and alternator is Bosch, Sept 1996.

iluvmydiesels said:

with everything off for several hours check batt with multimeter, if ok check alt charging. when was the last time you did batt? alt?

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The symptoms you describe fit a seized clutch pulley on the alternator - have you checked to see if it is still working only in the one direction as designed?

Also, check to see if the tensioner arm moves freely in the pivot.

I had similar symptoms on my B4V. A new clutch pulley, lubing the tensioner rod and bushings, as well as a new tensioner spring solved it.

As you likely are thinking, the harmonic balancer can also be a cause of similar symptoms - good you checked it.

Windex said:

As you likely are thinking, the harmonic balancer can also be a cause of similar symptoms - good you checked it.

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didnt the last guy have an older un-updated balancer version where the 'rubber' balance ring can separate causing squeal. new updated balancer pulley solved this, me thinks. still think its a charging problem or the alt pulley is bad. but all problems must be considered till solved. gl

Thanks, all. I'm traveling for a couple of weeks but will report back once I check/replace the alt pulley to start with.

Finally got back to working on the car. It was the alternator pulley. It was a Gates and lasted about 30k miles. The new one is a Dayco. Thanks for the help.