A/C Engages-Horrible Sound - PeachParts Mercedes-Benz Forum

RoysVeggy · #1 06-12-2008, 03:06 PM

I am having a horrible sound come from my engine bay when I turn my AC on. IT sounds like another car I had with a belt tensioner going bad.

All of the belts are in good condition. What could cause such a bad sound with the AC running? Any ideas?

rkohut · #2 06-12-2008, 03:13 PM

Compressor belt slipping?

#3 06-12-2008, 03:25 PM

Does it sound like a belt, or does it sound like the compressor is grinding rocks?

RoysVeggy · #4 06-12-2008, 10:42 PM

Quote:

Originally Posted by Craig

Does it sound like a belt, or does it sound like the compressor is grinding rocks?

Compressor is grinding rocks

TylerH860 · #5 06-12-2008, 10:48 PM

Be sure to fill your new compressor with R12.

The exact same thing happened to me 1 month ago. You can remove the belt or run the climate control in "economy" until you replace it.

RoysVeggy · #6 06-12-2008, 03:25 PM

Possibly. Where should I start at fixing this?

RoysVeggy · #7 06-12-2008, 10:51 PM

Tyler, My system was converted. That sound is coming from the AC compressor?

TylerH860 · #8 06-12-2008, 10:59 PM

It was in my case. The belt was turning, but the compressor was slowly locking up. It could also be the clutch.

It was blowing cold up until I had to remove the belt because it was smoking from all the resistance. Here's the link to my AC thread. AC Miracle ended

$900.00 later, I had a new compressor with R12 in it. My old one had 134 and the difference is striking.

My mechanic noted that some compressors don't adapt to 134 very well. I'm not sure as to the validity of his statement, but he claims that converting systems to 134 regularly locks up AC compressors. I'm not sure if I agree with him.

#9 06-12-2008, 11:01 PM

Quote:

Originally Posted by RoysVeggy

Tyler, My system was converted. That sound is coming from the AC compressor?

Do you mean it was converted to R-134a (if so I would consider converting it back)?

That sound is almost certainly coming from the compressor, put a long screwdriver agent the compressor and your ear to verify. You will have to replace the compressor, expansion valve, and dryer. You will also have to have the system flushed, evacuated, and refilled. Since you will be spending about $1000 anyway, you might as well refill it with R-12 to get maximum performance. I've had to do this twice in about 275K miles.

tobybul · #10 06-13-2008, 12:05 AM

Has anyone tried using Duracool instead of R12? I understand it cools better, operates with even less pressure and requires less refrigerant.

One of the reasons R134a does not work well in R12 systems is it operates in much higher pressure than R12 making it harder for the compessor to work. The o-rings are also not made to withstand the pressures for an extended period.