intermittent alternator noise

[jasonrs]

Ok 02 tahoe 134,000 miles. No real set timing or reasoning for this whining that im hearing, it wont do it all the time and it comes and goes. Doesnt change with steering, and goes away after rpms come up just to around 2000, sometimes comes back, sometimes not, most noticeable at idle. Volt gauge reads around 15 volts all the time, doesnt change with accessories or speed, and gauge doesnt change when noise occurs. Anybody had this happen? It has new belts, but quite sure pulleys are factory. When it occurs, I can put my hand on the alternator and "feel" the noise coming from it. Is it possible to have an intermittent noise like this from failing bearings in pulleys, etc., or from a failing alt., with no other symptoms? I am not into just throwing parts at it, so thought this might be the place for some good info. Thanks

 

[04whitetahoe]

Hey Jason, It seems you have already diagnosed your problem with your alternator if you can feel the vibration. That being said, there is at least one belt tensioner pulley and possibly an additional idler pulley that can cause noise. It's not uncommon for folks to replace those pulleys when they put on a new belt.

One way of making sure that it's your alternator would be to remove it, take it to an auto parts store that has the ability to check alternators and when they wind it up to speed, if it makes noise its the alternator and if not, change those pulleys.

Joe

 

[jasonrs]

Thanks man, I think thats good advice, will go that route first!