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TXredfish · 07-04-2010, 07:47 PM

I have about 20,000 miles and 7 years on my '04 WH chassis. It has been about 4 weeks since my last trip and no problems on that trip.
When parked beside my house, monthly I try to drive the MH just for the exercise or very minimum run the engine and A/C. Yesterday, I turned on the engine and engine A/C and no noise. I let it run until engine was warmed up according to the temperature guage. Then I turned off the A/C and a growling sound came from the engine compartment. I turned on the A/C and noise stopped. Turned off A/C and and growling started again.

So the growling sound only was happening when the A/C was off. I layed on the ground under the engine with A/C off and the sound appeared to come from the area near the serpentine belt idler/tensioner. After about 10 minutes the sound stopped and would not happen again. I turned off engine and let set for about 28 hours. I turned on engine and no growling sound from the engine with A/C on or off. Because of no sound I am not sure if it is the tensioner or A/C compressor. I would think that if it was the compressor the sound would be with A/C turned on.

Any suggestions? What is the cause? Any other checking I can do?
Because of no growling sound, should I go ahead and have the serpintine belt and tensioner replaced?
How big a job is this (hours) by a trained mechanic or should I try to do myself? What are the part numbers for belt and tensioner?
Thanks for your help .................

TandW · 07-04-2010, 08:00 PM

Sounds like the compressor clutch is failing. Have it serviced ASAP.

edgray · 07-05-2010, 09:23 AM

I think you will find replacing the belt tensioner is NOT going to eliminate the problem. Rather, it is more likely coming from the bearing in the AC compressor clutch. It makes the noise when "unloaded" aka, AC not running. Putting the compressor "on" changes the load on the bearing enough to eliminate the sound. It "may" run for a while in this condition, or it could self-destruct. I would run the AC to eliminate the noise until I could have an ASC check it out. In this day of parts changers, you will likely be told they HAVE to replace the compressor....but I've been told there IS a tool that allows them to remove the clutch and replace only the bearing. Good luck. Ed

bigskymt · 07-05-2010, 09:50 AM

You should be able to put an open end wrench on the tensioner and move it away from the belt to spin it freely and listen.

Ding-a-ling · 07-05-2010, 07:30 PM

That is exactly how mine acted two years ago when the A/C compressor clutch went bad. For that '04 model year the clutch assembly was not replaceable - had to have all new compressor assembly. Was covered by extended warranty.

Good luck!

TandW · 07-05-2010, 07:34 PM

The 2001 was not a repairable clutch either. Which was a moot point since the compressor had seized. But in that case why would one want to put a used clutch onto a new compressor?

RVhauler · 07-05-2010, 07:47 PM

In some cases a new clutch unit is available and if it is not and compressor is good then purchase a like re man unit and swap clutches. Refrigerant does not have to be removed for clutch change. Been there and done that. Just ensure clutch air gap is adjusted correctly.

TXredfish · 07-06-2010, 08:55 PM

Thanks all for your help.

I went to my local mechanic and he used a stethoscope and located two sources of the sound.

Sound #1 was from the serpintine belt. The belt was split and was replaced.

Sound #2 from the compressor clutch. With the A/C off, the distance between the clutch roller (belt goes over) and the clutch housing is very close. So close that rust on the clutch roller and clutch housing was rubbing and causing a sound. With A/C on, the distance between clutch roller and housing increases and no sound. He said with A/C off, I could still have the rust rubbing sound and no need for any changes. With belt
off he checked all contact rollers and found them to be smooth and would not produce sound or feel rough.

So I guess,problem is fixed...................

ROMAD · 07-06-2010, 11:05 PM

Quote:

Originally Posted by edgray

I think you will find replacing the belt tensioner is NOT going to eliminate the problem. Rather, it is more likely coming from the bearing in the AC compressor clutch. It makes the noise when "unloaded" aka, AC not running. Putting the compressor "on" changes the load on the bearing enough to eliminate the sound. It "may" run for a while in this condition, or it could self-destruct. I would run the AC to eliminate the noise until I could have an ASC check it out. In this day of parts changers, you will likely be told they HAVE to replace the compressor....but I've been told there IS a tool that allows them to remove the clutch and replace only the bearing. Good luck. Ed

edgray, There is a set of tools that removes and installs the AC compressor clutch assembly on GM air conditioner systems. I had it done on my Blazer. Cost about $100 to replace the bearing and they didn't even have to remove the AC compressor! Another shop wanted to replace everything for about $800. Still working great 4 years later...

edgray · 07-07-2010, 11:17 AM

Quote:

Originally Posted by ROMAD

edgray, There is a set of tools that removes and installs the AC compressor clutch assembly on GM air conditioner systems. I had it done on my Blazer. Cost about $100 to replace the bearing and they didn't even have to remove the AC compressor! Another shop wanted to replace everything for about $800. Still working great 4 years later...

YES, that is what I was told, and like someone upthread posted, the "air gap" is critical. So, it takes a mechanic that knows how to use the tools and not a Tech that only knows how to replace the entire compressor with the clutch already installed. Such is life these days. Ed