Checking alternator bearing

[Paulporsche]

Sorry if this has been covered before; the search fn is temporarilly down.

I'm getting a high pitched whistle @ startup and low revs coming from the fan area. While driving, I hear a metallic noise, kind of like a scraping, that occurs whether the car is in gear or not. It seems to be coming from the fan area.

I'll be checking for fan blade rubbing, but I'm thinking it might also be an alternator bearing. AFAIK the only way to check this is to loosen the fan belt and see if there is any wobble on the shaft.

Are there any other checks I can do? Any other possible causes? If there is play, then I guess a replacement of the bearing is the only solution.

[Walter_Middie]

Paul,

There may be a good way to test your fan bearing, but I don't know what it would be. It would have to be really bad before you could notice any slop, then I would think it would be hitting the shroud.

I have replaced my fan bearing twice. The first time there was a slight noise, the second time I just needed an alternator rebuild. Both times the bearing was worn without any obvious signs - and I don't keep my belt too tight.

What I'm trying to say is that it's not always obvious. Can you get back there with a stethoscope and poke around? If you think its the fan, pull it and put a new bearing in. It's a small PITA, but an easy Saturday morning job.

[Paulporsche]

Thanks, Walter. I'll have to rig up a hose, tube or stick and have a closer listen.

[boyt911sc]

Originally Posted by Paulporsche

Sorry if this has been covered before; the search fn is temporarilly down.

I'm getting a high pitched whistle @ startup and low revs coming from the fan area. While driving, I hear a metallic noise, kind of like a scraping, that occurs whether the car is in gear or not. It seems to be coming from the fan area.

I'll be checking for fan blade rubbing, but I'm thinking it might also be an alternator bearing. AFAIK the only way to check this is to loosen the fan belt and see if there is any wobble on the shaft.

Are there any other checks I can do? Any other possible causes? If there is play, then I guess a replacement of the bearing is the only solution.

Paul,

I would suggest you use a mechanic's stethoscope to inspect the alternator's bearing. The stethoscope will help you determine if the noise is coming from the alternator or not. If I were you, I would remove the alternator and have it bench tested by an starter/alternator shop.

Tony