[s-cars] Serp belt woes

[Tom Green]

Aaron,

I take it you have decided that the tensioner is good and not the  
problem?  And, the noise was probably the pulley rubbing on the TB  
cover?  I would expect that the noise would disappear
without the tensioner since the belt is not driving the components  
without it.  Check the smoothness of all the belt driven components  
while the belt is off to make sure they all rotate smoothly.
A failed bearing in the alternator or engine driven fan support can  
cause noise and stress on the belt as well as the compressor or  
hydraulic pump.  Check to make sure all pulleys are in line
with the new belt.

The a/c compressor puts a lot of stress on the belt but I have not  
heard of stretching problems especially from the  ContiTech brand  
most commonly sold as the OEM belt.  Usually if there is a
large increase in drag on the belt it heats up and then shreds  
apart.  The squealing compressor is maybe the belt slipping on the  
clutch pulley?  They get noisy when defective but bearing
noise is unusual, "jet engine or turbine sound" is more common  
description.  Do  a thorough troubleshooting job before deciding on  
replacement, since the cost of parts and labor is not trivial.

However, if the compressor squeals or drags the belt sufficient to  
make it squeal, I would be thinking replacement before it started  
making metal.  You might check the error codes on the CC
head to see if there are any stored.   There is one for a mismatch in  
compressor and engine rpm.

Tom

-----Original Message-----
> Date: Wed, 16 Jan 2008 10:26:49 -0800 (PST)
> From: Aaron Ryba <aaronryba at yahoo.com>
> Subject: [s-cars] Serp belt woes
> To: s-car-list <s-car-list at audifans.com>
> Message-ID: <77939.33931.qm at web51410.mail.re2.yahoo.com>
> Content-Type: text/plain; charset=us-ascii
>
> My serp belt tensioner is displaying the characteristic rattling  
> noise upon load however I just replaced it barley over a year ago  
> (~7k mi) along with the belt when doing the TB job. There is also a  
> rolling, rubbing noise which I assumed was the bearing. WTF! I am  
> thinking as I paid over $200 for the OE part and belt.
>
> So I pulled the part with the intension of sending it back to Blau  
> for a warranty consideration however the 1 year warranty is now  
> eclipsed.
>
> The service technician suggested perhaps the belt was stretched. I  
> might buy that because my AC compressor seems to be draining a lot  
> of power when it kicks in and it did see some good use this past  
> summer. I have only owned the car for the last 1.5 yrs so I don't  
> know the history of the old tensioner & compressor problems. Does  
> this stretched belt diagnosis sound like a possible scenario to  
> anyone?
>
> I am ordering a new belt to test the theory this weekend.
>
> I did pull the tensioner and run the engine without it hooked up  
> and viola, no noise. The steering pump is new so I know thats not  
> the problem. Also, I noticed that when I pulled the tensioner it  
> looked like the bearing was rubbing up against the TB cover as if  
> the tensioner wasn't tight enough. The one bolt near the therm was  
> a little loose but only by 1/4 turn at most. Maybe the additional  
> stress the stiff AC compressor is putting on the tensioner has done  
> this??
>
> (I know the AC compressor has to be replaced soon , or at least  
> have the bearings replaced as it squeals at mid to high rpm.)
>
> Aaron Ryba
> 95 S6