I recently replaced alternator, belt tensioner, and Serpentine Belt.
All with 100% new parts. Everything was fine for the first few trips after the work, however now I get a loud screeching sound when engine first starts. This only lasts for about 20-40 seconds, then it stops and runs fine. Belt is installed according to diagram and is sitting properly in all the groves of the pulleys. It is also the exact same model number of belt that was in there before. Any ideas?


1996 Tahoe

Thank you

 

Are your pulleys polished like a mirror from slipping, I have used a steel wool pad to scar them a little to prevent slipping, just a thought. Rubber polishes metal over time.

 

Did they sell you the correct belt.? There are 2 different belts available based on the amperage of the alternator. If you got the larger belt you need to put the shorter one on. It is only very slightly shorter.

 

Thanks for the responses.

Yes it is the same belt that was on there, compared by part number. (they did give me the wrong belt at first) Like I said, it only happens when the engine is first started, and only lasts for like 45 seconds or so. (never happen before the news parts were installed)

Any more ideas?

Thanks again

 

Was the wrong belt shorter than the right belt? If so put the shorter one on your noise will go away. Spary water on the belt while it is making noise if it stops the belt is sliping (too long, tensoner not holding it tigh enough or poor quality belt)if it does not then one of the pulley bearings is bad. Was the alt pulley and tensioner pulley the same size as the original?

 

Thanks for your help. Will try when I return home later in the week.

Thanks again

 

Thanks again for the input, I have pinpointed the sound to the AC Compressor/clutch. You can hear the squeaking sound, only for about 5-10 seconds, then if you turn off the ac it stops right away.