Help Troubleshoot Powersteering Pump or Alternator
 

Greetings,
I am trying to narrow down a worn bearing noise in the front passengers side of the engine. It only occurs when it's cold and it varies with the RPM. It goes away after the car warms up. I suspect it is the bearings in the alternator as dry steering the car does not change the sound. I could wait till one or the other fails, but would rather be proactive. Any suggestions on making a definitive diagnosis? Thanks

The idler pulley's for the serpentine belt are the most common issue. Take your belt off and start spinning them. If one is noisy, that is your issue. I replaced all of mine at 78,000 miles or so.

Try spritzing a little water on each bearing one at a time, when the noise stops that's your culprit.

Thanks guys
 

I have replaced one of the idlers to date. Based on the location of the noise, it is bearings in the alternator, power steering or the tensioner. Good idea about removing the belt (as I plan on replacing it anyway) to determine the culprit