Alternator knocking? (video)

[mitecl96]

Can an alternator make a knocking noise?

Video.
Alternator knocking? - YouTube

I got a knock and it sounded like it was coming from the alternator. I removed the belt to the alternator and the knocking went away.

I took the alternator to all Advance, Autozone, and O'rellys and got it tested. To see if it would knock there to be sure. It didn't knock at all and ran perfect.

I'm confused and lost, please help

 

[grothe3297venge]

Did you check to see if the alternator was completely tightened down before you took it off? Meaning like was the alternator bracket tightened all the way down and so forth.

 

[mitecl96]

Yes everything was tight. I'm about to put it back on to see if it comes back.

Just isn't making any since.

 

[luv2rallye]

- Put stethoscope (or long screwdriver against your ear) on alt housing around it's bearing to listen for grinding (belt on and running). Also on water pump housing.

- Take it to an alt/starter repair shop to be tested. Auto store testers are near worthless.

- Also are you sure it isn't the harmonic balancer? They usually need a tightened belt on them to make noise when they start going bad. Check if it moves in/out while reving and all belts on. Also wobble it hard by hand when stopped to check for movement.

 

[mitecl96]

- Put stethoscope (or long screwdriver against your ear) on alt housing around it's bearing to listen for grinding (belt on and running). Also on water pump housing.

- Take it to an alt/starter repair shop to be tested. Auto store testers are near worthless.

- Also are you sure it isn't the harmonic balancer? They usually need a tightened belt on them to make noise when they start going bad. Check if it moves in/out while reving and all belts on. Also wobble it hard by hand when stopped to check for movement.

I'll try listening to it again today when I get the alternator installed again. I think it's the alternator because the knocking stopped when it was disconnected.

I'll see also if I can find a shop that does alternators. If the bearing is out causing it to knock, why would a parts store test not make it knock.

I don't think harmonic balancer because it's new. Just about everything is new in the motor besides the valvetrain. Only got 4,000 miles on the rebuild. I was messing with the harmonic balancer and didn't notice any play.

 

[Colt4G63 also]

Alternators can knock, I've seen it happen. The reason it didn't knock at the store was probably because they loaded the bearing on a different angle than it is in the car.

 

[Diamond Star Werks]

Just start the car without the alternator on and listen if it still does it. If not reinstall it and listen again. As stated in the other thread it is definitely ball bearings knocking into each other. You can tell by how it sounds at idle and how it doesn't directly increase with engine speed. And if your timing components are new then the alternator is a very likely subject.

 

[gogo_google]

did you check that everything is ok with charging, is it ~14V stable or pulsing??

 

[mitecl96]

Everything checked out.

I just finished putting the old alternator back in.

Before it was in I started it up, NO knocking

After it was in, Knocking was back than went away, can't get it to come back. No more knocking at the moment.

 

[Diamond Star Werks]

I'd say its the alt bearing.

 

[mitecl96]

That is what I'm guessing. Not smart but I'm going to hold off for now need to get other thinks fixed, seeing that the knock has stopped.

 

[reallyslowfwd]

that sounds like the harmonic balancer, my wifes Stratus does the same thing

 

[mitecl96]

How can it be if it goes away when the alternator is off. Plus it's a new harmonic balancer.

 

[Lou98GSX]

maybe the belt was to tight

 

[Diamond Star Werks]

Too Tight or not I've never heard good bearings knock together like that. It needs to be changed regardless.

 

[mitecl96]

I don't think it was to tight, the belt would slip a lot. But is the the alternator or the harmonic balancer.

 

[DropSomeMoney]

Ok. I used to rebuild these. There is a very simple way to figure out if you have a loose belt or if the bearings are bad or need to be greased. Run your car at operating temp for bout 5 minutes. Then turn it off and put your hand on the alternator housing and just feel how hot it is. It should not be that hot from being aluminum. Them take your hand and put it on the alternator pulley. If the pulley is hotter than the housing you either have a slipping belt or your bearings need to be greased or they are just bad. That knocking could be multiple thing though. Try the warmth test and let me know how that turns out.

 

[Christopher D Norrup]

Can an alternator make a knocking noise?

Video.
Alternator knocking? - YouTube

I got a knock and it sounded like it was coming from the alternator. I removed the belt to the alternator and the knocking went away.

I took the alternator to all Advance, Autozone, and O'rellys and got it tested. To see if it would knock there to be sure. It didn't knock at all and ran perfect.

I'm confused and lost, please help

I'm having the same thing going on. I have put all new pulleys, new power stearing pump and pulley. Then just the other day it started knocking and squealing. If I remove the belt. It all goes away ???