m1009 Chirping like a cracked-out sparrow:

[devousivac]

OK. I'm going crazy not being able to figure out what's making this noise. Here's the story:

1) Driver alternator was bad. Volt regulator was going out.
2) I go to Autozone and get a new driver's side alt (DL 7157) and switch the pulley out to account for the difference in size
3) I replace every belt. Both alts and the power steering belt, 3 total, but you already knew that.
4) chirp. chirp chirp chirp. (Note that this sound was not present when I was running it with the old alternator.)

So I hear this chirp and I assume one of the belts is too loose even though it sounds too metallic to be a belt whine. Not the case. All the belts are tight and good. I run it again. Chirp. Chirp. Chirp. Then I assume that I bought an alternator from Autozone with some bad bearings, so I bring it back and exchange it for another. I install that one. Chirp. Chirp Chirp.

Through a very scientific process of elimination that I made up myself, I make the assumption that neither of the new Autozone alternators were bad as the M1009 makes the sound regardless of which new Autozone alternator is in there.

To be certain the bearings aren't going out in the passenger side alternator, I disconnect the belt on the passenger side alt and run it only on the driver's side alt. Chirp. Chirp Chirp.

So then I disconnect the belt on the driver's side alt and run it on the passenger side alt, to see if its coming from the power steering. No chirp - only the obnoxiously loud noise of my manly diesel engine. What does this mean if there is a chirp ONLY when the driver's side alt belt is connected, chirping with either of two new alts?? I can understand getting one bad lemon, but what are the chances of getting two bad lemons (Autozone alts) in a row??

I don't know what to make of this. My powers of deduction obviously are poor as I have made the below theories and somewhere they are contradictory. Any help would be greatly appreciated.

Here are my theories. The chirping is NOT caused by:

1) Either of the brand new Autozone alternators as two alternators fresh from the store made the sound (yes. I do know that Mike at OD Iron sells better versions of these and that I should just go there. I didn't and I'm trying to clean up my act. Thank you.)
2) The passenger side alternator, as when the truck runs off just the passenger side alternator, the chirping is not present.
3) The power steering pump bearings, as when passenger alt and power steering belt are connected, there is no chirp.
4) Sparrows, as I have single-handidly slaughtered everything with wings in a twenty mile radius to eliminate any possibilities of fluke chirping.

 

[3dubs]

Get some good ears to help. They also make an automotive stethoscope. Not sure about the spelling. But looks life the the one a doc would have but the part that goes on you chest is a long metal rod. You can put it against things and listen. But I ask other people to listen too. If it is making noise it can be found. Do not replace anything until you know what it is. Do not forget the fan or timing chain. If things get loose they make noise. When listening move around. Watch out for the sound echoing.

 

[devousivac]

Thanks

I'll get a stethoscope tomorrow.

I guess to sum up my too long post - the sound only occurs when the driver side belt is attached, and the alt is brand new, and did it with two different brand new alts. Is there any chance that Autozone alts are so incredibly poor that two in a row could make the chirp, despite my having swapped the wrong sized Autozone pully for the appropriate larger size?

 

[Tnrobocop]

I'll get a stethoscope tomorrow.

I guess to sum up my too long post - the sound only occurs when the driver side belt is attached, and the alt is brand new, and did it with two different brand new alts. Is there any chance that Autozone alts are so incredibly poor that two in a row could make the chirp, despite my having swapped the wrong sized Autozone pully for the appropriate larger size?

After working at Autozone once upon a time, it is possible to get at least two, maybe more, crappy alternators.

 

[ragedracer]

Is it possible that the pulley (the one you swapped out) is making contact somewhere on the new alternator?

 

[devousivac]

Pulley

Thanks for the suggestion, but I think that's unlikely. My lack of intelligence did not allow me to notice the differences in the pulley sizes immediately so its been run off both the Autozone pulley, which is 1/4 inch smaller than the actual pulley, and the sound is there with both.

My new theory: the autozone alts are so poorly made that it just makes a weird metallic chirping sound.

After work today, I'm gonna get two things, 1) a stethoscope, and 2) a new driver's side belt as I'm thinking there is a very slim chance that whatever factory made the belt made is slightly too wide and that is creating something (I think the possibility of #2 being correct to be about the same chances of me winning the Powerball, but if it is not correct, then I just have a replacement belt around, which is a good idea anyway.)

 

[Somemedic]

With the belts off and cucv not running physically try to wiggle the pulleys on the alts, the power steering pump, and the fan. There shouldn't be any play. Also check the blades on the alts for clearance as well as the fan blades and shroud. Then put your belts on, one at a time. When it makes the noise drive to a local shop and ask the mechanic where he thinks its coming from. Report back what you find.