Alright, so my alternator started making a hellacious about a month ago. I replaced that alternator with a rebuilt one and the noise went away.

I thought the problem was fixed because the noise had temporarily gone away, but it's been about a week and the same alternator whining noise is starting to come back.

I'm wondering if there's a certain torque spec or something on the idler tensioner that's causing the drive belt to effect the alternator (i.e being too tight or loose effecting rotations) Or maybe I just happened to get an alternator that was on it's way out?

Maybe it's a faulty idler pulley?


Any input would be helpful, hopefully I can finally stop this noise, I might post a video later on if it needs to be specified.

Thanks alot guys
-Spence'

 

Is it making the same noise at all rpms? or is it just at idle, or under load, etc.?

My 240sx did that after changing the alternator on it, but I also changed the belt, and the belt was a half inch too large and wouldn't tension properly. I ditched that belt (that I got from Pep Boys), and got the proper length one from AutoZone, tensioned it up and there was no more noise after that. But it wouldn't make any noise at idle or below about 2,500-3,000 rpms, then it would whine.

In fact, several people asked me if my 240 was supercharged when I was having that issue. I, of course, just told them yes.

 

Check the belt for wear and follow the specs below for belt deflection.

 

I should sticky this.

 

Haha, at high speeds it does kinda sound like a supercharger. But in fact yes, it does make the whine at all rpms including idling.

I'm almost tempted to buy a belt for max's without AC and just remove my compressor seeing as how I don't have AC anyways.


And nelledge that's a great diagram. Answers my torque spec question.

If I don't get a torque wrench that can get down to that nut for the pulley does anyone know a rule of thumb how tight I should go with the tensioner bolt?

 

I agree. It is amazing how many car enthusiasts I talk to that don't understand the importance of the correct belt deflection.

 

Well, I find it amazing how many people's knowledge about cars ends after putting key in the ignition switch and starting it. And they don't even know that ignition switch is the name of the "thing" that they put the key in.