cleanEG

I am at a loss as to what is causing these problems...Any help would be much appreciated!

1. Replaced alternator with rebuilt autozone duralast alternator after original alternator went out.

2. Since then, I have gone through 3 Duralast alternators due to bearing noise (grinding noise) coming from the alternator during idle immediately after replacing it.

3. Went to Acura and picked up a rebuilt alternator from them and after installing it, no more noise. At least until I drove around the block, came back and when I started the car again, the noise returned.

-- New alternator belt with tension set properly, loose, or extremely loose (not charging battery) STILL Makes noise!!

-- Remove belt from the alternator and grinding noise is gone (of course so is the battery if longer than a minute)

Any ideas as to what could be causing the bearings in the Alternator to go out quick, or am I just that lucky right now to receive 4 bad alternators??

Thanks

veggiemaster

Are you POSITIVE its your alternator? Ive gone through 2 alternators in a month, but never for that reason. I happened to get one that had bad brushes. But ive never heard of alternator bearings going out that rapidly or at all.

cleanEG

It is the Alternator.....as mentioned before, no belt (no alternator) = no problems

**frustrated**

Supernatural

i had a burned out alternator wire that kept killing alternators

DOHCtorTHRUST

did you check your fuse box wires? its the harness and the starter juice wire, they often get mixed. i had a buddy that got it mixed once and he had issues.

cleanEG

ahhh good point, let me check

cleanEG

Alternator wiring is connected right at the fuse/relay box....

Alternator also charges the battery when in use, however the grinding noise (bearing failure symptoms) are still present.

I thought perhaps the belt was on too tight, however I checked the tension by twisting the belt completely around and it was good.....

d16dcoe45

I can almost GUARANTEE that its not your bearings that are getting toasted so quickly!! It sounds like you have a major short somewhere-that you are over looking. I would really go over your wiring set up with an eagle eye--and check the resistance of all your alternator wires--I bet you will find a problem...

d16dcoe45

And the chance of you receiving 4 consecutive bad alternators--from two different places, I would honestly say is like 1 in 100,000!!

cleanEG

Thanks for the advice! I am going to double check all of the wiring again this week, however I did make some progress yesterday on it.

Current Issues:

-- During initial start up (cold or warm) the alternator screams until I rev the motor up to 3-6k for a few seconds, then it goes away completely.

-- I triple checked the belt tension and it was perfect, I was able to twist the belt 360 degrees or more.

tyro

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by cleanEG &raquo;</TD></TR><TR><TD CLASS="quote">-- I triple checked the belt tension and it was perfect, I was able to twist the belt 360 degrees or more. </TD></TR></TABLE>

I notice in you first post you mention the tension as "proper, loose and extremely loose". How are you checking tension?

What about beyond proper, as in tight? I don't think you should be able to twist the belt 360 degrees.

Another question: do the pulleys line up properly? Is there a possibility of your alternator being "cockeyed"?

On the "defective" alternators, did the pulley spin freely?

cleanEG

Well, here is how I went about checking the tension:

I adjusted the alternator the point where the battery was holding a constant ~ 13.5 - 14 volts.
I played with the adjustment until I found the sweet spot where it was just shy of not charging the battery.
I probably adjusted the belt over 100 times by now

As for the pulleys, they are lined up perfectly.

Regarding the shitty Duralast alternators, I noticed that before installing the them, the pulley would spin without any noise. However after installing the alternator, idling the car, hearing the grinding noise, and removing the alternator --- I could spin the pulley and hear what I thought was a loose bearing. This has happened on all of the Alternators EXCEPT the acura one.

I have a $200 duralast alternator that I need to take back and a $350 acura one in the car. If I throw in the duralast, I get the metal grinding noise ...with the acura one, I dont get the grinding noise, its more of a very loud screaching noise.

keep em coming and thanks guys for taking the time

tyro

Does the screeching noise with the Acura alternator come and go, or is it constant?

What I'm getting at here is this: is the belt slipping? Have you tried another new belt with the Acura alternator? Is there a possibility of the belt being glazed from slipping around on the various alternators you've tried?

cleanEG

Could be the belt, so I am going down to Acura tomorrow to pick up an OEM replacement instead of the Duralast replacement belt I bought with the other alternator. Currently I have the old OEM belt on and it makes less noise then with the Duralast one. It might be slipping when I first start the car because as of now, it is only during the initial startup and lasts for a couple seconds. I will update the thread after the new OEM belt....

rev-speed

since u swap so many alternators
did u always use the same pulley?
im thinking the pulley is rubbing against something

BigMoose

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by cleanEG &raquo;</TD></TR><TR><TD CLASS="quote">Well, here is how I went about checking the tension:

I adjusted the alternator the point where the battery was holding a constant ~ 13.5 - 14 volts.
I played with the adjustment until I found the sweet spot where it was just shy of not charging the battery.
I probably adjusted the belt over 100 times by now

</TD></TR></TABLE>

I sure don't understand your method of adjusting the belt tension. You should not be able to twist the belt over 360 when the tension is correct. IIRC, and I didn't go and open my helms, but the spec calls to tighten the belt so that about a 22 lb force in the midspan of the belt deflects it like 0.4 inches or so. Calibrate your thumb on a scale, and away you go. It sounds like a slipping belt squeal to me. All the alternators might have been good. The odds of 3 or 4 bad alternators is zilch.