Whiny whiny Alternator!

[InfraredMonkey]

Not sure if it's the cold Chicago weather out here or if it was the results of my temp. fix.

The temp. fix was when I bypassed my A/C with a shorter belt (61" I believe). I think with the shorter belt, the alternator bearings are getting worn out. I can't really tell, but the alternator itself looks new, but I can't confirm that what-so-ever. :(

Should I get a longer belt to go around the idler pulley to relieve tension from the alt bearings? Or is my alt just old and is in need of replacement?

If I'm going to toss out the alt, I mine as well do an upgrade on the wiring as well. I'm not sure if I want to stick to A/C Delco alt or go with something else like Duralast?

[UDLOSE98]

Re: Whiny whiny Alternator!

alt whine is a pretty common thing on v6 fbodies. Shouldnt really be that big of a concern

[InfraredMonkey]

Re: Whiny whiny Alternator!

alt whine is a pretty common thing on v6 fbodies. Shouldnt really be that big of a concern

I figured that at first, but I don't know..the sound itself didn't really start until about a day ago. It concerns me, because it just started whining. I mean, yes my power steering pump whines, but it's been whiny every since I bought it.

I'm trying to stop a possble problem before it gets potentially worse and get me stuck in cold. :cry:

[CDNFB]

Re: Whiny whiny Alternator!

It doesn't matter if you use the long belt or short belt, as long as you don't bottom out the tensioner. If the tensioner is pulled to the max, then the tensions could be higher than spec and your bearings could be at risk. If the tensioner arm is floating then the tension on the alternator is the same as it would be with the longer belt.

An alternator can make 3 different whine noises.
The first one is when the Alternator is at low rotation speed and high load. This is a natural state.

The second one is when the bearings are starting to go. The whine is a lower pitch in comparison with the load whine and will progress to a growl as the bearings get worse.

The third is whine is when one of the diodes in the trio pack fails. (These are not the bridge rectifier diodes) This whine sounds like the high load whine, but whines when low and medium loads are applied. Will not progress or get worse, but the performance of the alternator is affected (max output and response to loads)

I would first remove the belt and check the alternator for loose and/or rough bearings by rotating the pully. Then I would do a load check on the battery and then the electrical system to make sure that neither is drawing an excessive amount of power. A battery that cannot hold capacity will draw considerable power from the alternator (load whine). The trio diode is not that big a deal unless you are always drawing heavy loads from the alternator, then you might want to do something about it.

[runtwrestlin]

Re: Whiny whiny Alternator!

I had one that had an awful high pitch whine that would get higher/louder with any increase in rpm's from idle. It sounded like a crappy supercharger---without any HP gains. But mine was also brand new, so I just took it back and they gave me one that worked properly.

Just to check an see if the alternator is still good or not, just go to NAPA (I think advance does it as well) and they'll test it for you for free.

[Black98Fivespeed]

Re: Whiny whiny Alternator!

My buddy's Explorer has a NASTY alternator whine, it sounds like a freaking supercharger. He got his truck stuck off-roading a few weeks ago and actually over-reved the alternator and spun the bearings.

[Blue02]

Re: Whiny whiny Alternator!

It doesn't matter if you use the long belt or short belt, as long as you don't bottom out the tensioner. If the tensioner is pulled to the max, then the tensions could be higher than spec and your bearings could be at risk. If the tensioner arm is floating then the tension on the alternator is the same as it would be with the longer belt.

An alternator can make 3 different whine noises.
The first one is when the Alternator is at low rotation speed and high load. This is a natural state.

The second one is when the bearings are starting to go. The whine is a lower pitch in comparison with the load whine and will progress to a growl as the bearings get worse.

The third is whine is when one of the diodes in the trio pack fails. (These are not the bridge rectifier diodes) This whine sounds like the high load whine, but whines when low and medium loads are applied. Will not progress or get worse, but the performance of the alternator is affected (max output and response to loads)

I would first remove the belt and check the alternator for loose and/or rough bearings by rotating the pully. Then I would do a load check on the battery and then the electrical system to make sure that neither is drawing an excessive amount of power. A battery that cannot hold capacity will draw considerable power from the alternator (load whine). The trio diode is not that big a deal unless you are always drawing heavy loads from the alternator, then you might want to do something about it.

Wow, nice Alt write up!
I'd unplug the connector from the back while it's running first and see it that changes the sound, that will tell you if it is electrical or mechanical. If you decide to toss it then I want it, seems that alternators are a common fault on our cars and I'd like to have a spare. All the auto parts stores around here say that it is a slow moving part and they can get one in a few days... riiight, buddy that's a few days WITHOUT MY CAR! :twak:

[InfraredMonkey]

Re: Whiny whiny Alternator!

It doesn't matter if you use the long belt or short belt, as long as you don't bottom out the tensioner. If the tensioner is pulled to the max, then the tensions could be higher than spec and your bearings could be at risk. If the tensioner arm is floating then the tension on the alternator is the same as it would be with the longer belt.

An alternator can make 3 different whine noises.
The first one is when the Alternator is at low rotation speed and high load. This is a natural state.

The second one is when the bearings are starting to go. The whine is a lower pitch in comparison with the load whine and will progress to a growl as the bearings get worse.

The third is whine is when one of the diodes in the trio pack fails. (These are not the bridge rectifier diodes) This whine sounds like the high load whine, but whines when low and medium loads are applied. Will not progress or get worse, but the performance of the alternator is affected (max output and response to loads)

I would first remove the belt and check the alternator for loose and/or rough bearings by rotating the pully. Then I would do a load check on the battery and then the electrical system to make sure that neither is drawing an excessive amount of power. A battery that cannot hold capacity will draw considerable power from the alternator (load whine). The trio diode is not that big a deal unless you are always drawing heavy loads from the alternator, then you might want to do something about it.

Beautiful write up, this should be a sticky IMO. I'm gonna take a look tomorrow morning. I'll let you guys know what's up.