2001 Suburban: Rattle on Acceleration

[Redleg]

Ok guys, i have a 2001 Suburban LT 4x4, 5.3l, front and rear air.

What i BELIEVE to be my problem is the belt tensioner/AC Compressor, but want to get yalls opinion.

When driving, WITH OR WITHOUT the AC on, once the vehicle gets warmed up or i have been driving a good while, i start to get a rattle when I accelerate. The harder i accelerate the more it rattles.

I have heard many differant options, including catalytic converter etc, however the noise appears to be coming from under the hood and i believe it sounds like the belt tensioner slapping against something. I did some researching and i found that was a "sort of" common issue with the AC Compressors as they start to go bad and try to lock up and it pulls the belt tensioner, and some other info about the AC compressor and the fluid etc that could cause the problems.

The issue is, on those reports everyone mentioned they had their AC on at the time, well mine is happening with or without the AC on. So, based off the book i just wrote you and hopefully you read, any opinions????

[fun in dirt]

Curious to hear any opinions on this too....we have an '01 2500 2wd that has a weird rattle, similar to what you're sayin. However it seems to just do it when cold before engine/trans really warmed up. More so when pulling off, then as soon as let off throttle it quits & doesn't do it again. Almost sounds like fan hitting shroud, but that's not it & we've replaced all the idlers.

[BigRed76]

Remove the a/c compressor belt and drive it again. If it still makes the noise you can rule out the tensioner or compressor.

[Aaron_L]

My '02 Suburban had developed a strange rattle under acceleration. Mine was a kind of a metallic tapping sound, not like a knock. I kept looking under the hood and found nothing. Then I took a dead blow hammer and whacked the cats - bingo! Something was moving around in there. When I removed them there was nothing inside of the cats at all, the rattle was actually a part of the converter element that had worked it's way down into the y-pipe. I never had one check engine light the whole time.

A couple of years earlier the a/c tensioner started to go out on this same truck. The belt would squeal on startup, or whenever the compressor kicked on. When I replaced the tensioner the old one was sprung and more or less just flopping around. It had hardly any tension on the belt at all but I never heard it rattle.

[GASoline71]

When I was married to my first wife, her 2001 Suburban 1500 with the 5.3L developed a rattle under acceleration from a stop, or when accelerating from around 20mph.

It turned out to be 2 things. First the heat shield that was welded to the stock muffler had started to crack and created a rattle/buzz. Once that was fixed, the cats started to rattle. Both of them. So a new Y-pipe with new cats fixed that.

Gary

[wyattglock]

My 2002 Silverado 1500hd had the same problem. Not running the a/c but had a hellacious rattle from under the hood. I thought power steering at first, but while i was under the truck during the rattle, I realized it was the a/c compressor. I took the belt off and it has not happened since. That was 2 months ago. I am in the process of getting a new compressor to replace it with.

[fun in dirt]

Okay, our's was the ac compressor. Replaced & no noise now.
So little explanation.... Husband read that around these years the compressors had a problem with locking up & causing the idler to flop (part that makes all that racket). Because the compressors are mounted lower than any other part of the system, after they sit for a little while all the oil in system drains into it & tries to lock it up. Newer, redesigned and reman compressor changed the design a little to correct this problem.

[BigRed76]

Originally Posted by fun in dirt

Okay, our's was the ac compressor. Replaced & no noise now.
So little explanation.... Husband read that around these years the compressors had a problem with locking up & causing the idler to flop (part that makes all that racket). Because the compressors are mounted lower than any other part of the system, after they sit for a little while all the oil in system drains into it & tries to lock it up. Newer, redesigned and reman compressor changed the design a little to correct this problem.

I also learned recently that there is a PCM reflash that GM issued to help with that issue you mentioned. It makes it so that the PCM will switch the compressor on and off very rapidly upon start-up for a short time, so it will slowly push all that oil through the compressor so it won't destroy itself.