Automotive Air Conditioning Information Forum (Archives)

TnTahoe on Tue June 07, 2011 7:48 AM

Year: 2003
Make: Chevrolet
Model: Tahoe
Engine Size: 5.3
Refrigerant Type: 134a
Country of Origin: United States

Ok i replaced the compressor and others parts last year because it was making a horrible rattling noise, well the noise returned but the a/c still worked fine, well yesterday i noticed that my a/c stopped blowing cold so I figured the belt had broken, well when I looked under my truck i noticed the belt was fine but the a/c tensioner was broken, appears that the spring inside of it broke. Anyways I spun the clutch on my a/c and it seemed to move freely like it's supposed to so I installed a new tensioner and belt last night. When I turned the truck on to see how the belt was tracking and everything looked fine. Well I turned on the a/c and it was working again so I decided to look at the belt again with the a/c engaged and I noticed that the tensioner was moving a good bit. So is this normal operation for the belt tensioner for the a/c to bounce around and also I turned on the a/c this morning on the way to work and the rattle was still there but not for long like before so I just turned the a/c back off. Anyone got any advice?

GM Tech on Tue June 07, 2011 9:49 AM

A forum search can provide this video I took awhile back.




Belt tensioner rattle

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

NickD on Tue June 07, 2011 11:19 AM

Did you thoroughly flush out the system with your last compressor and at least replace the accumulator? Did your last compressor seize? How did you deal with the condenser?

No, a dancing tensioner is not normal, your compressor is not providing a constant load on that belt, system may be pumping sludge for all you know or a piece of debris is hanging up a reed valve.

TnTahoe on Tue June 07, 2011 12:01 PM

I flushed out all the lines and replaced everything else, and no my last compressor did not seize, I still have it, I replaced it because of the damn noise but it didnt stop so im completely lost on this. The compressor not putting a constant load sounds about right to me because I noticed before the tensioner broke that the colder air would cycle in and out if you understand what I mean by that, it would blow cool then cold and keep alternating like that.

TnTahoe on Tue June 07, 2011 12:02 PM

Quote
Originally posted by: GM Tech
A forum search can provide this video I took awhile back.

pretty much sounds just like this video, but when the a/c is off it runs smooth like butter







Belt tensioner rattle

NickD on Tue June 07, 2011 2:50 PM

Least your system has a separate belt for the compressor to out rule other items in the belt train. So that just leaves the harmonic balance, tensioner, belt, and the compressor.

Some of these harmonic balances have that rubber sleeve that rots away.



Or the belt can have a flat spot in it. Just a couple of more things to check.

robs on Tue June 07, 2011 3:17 PM

We see that issue here and the best way to solve it is to buy direct from the dealer the tensioner and belt. After market ones will continue to cause the same problems.