compressor or clutch??? - PeachParts Mercedes-Benz Forum

#1 10-04-2004, 01:11 AM

I've had a post on here about my a/c, but decided to start a new thread with some new info. A few weeks ago, my air quit without warning. Then for a few days, it would try to come on, cool for about 10 seconds then bark and quit. Then it wouldn't even come on and make no noise. Today, I had a friend to push the button while I was watching under the hood....the compressor engaged, but turned VERY slowly (there was no squealing sound or anything) then quit....I thought it was locked up and it may be. There are pieces of black debris stuck to the radiator in front of the compressor. How can I tell if it's the clutch or if the compressor is shot?

BrierS · #2 10-04-2004, 04:28 AM

Is the outer portion of the compressor spinning freely with the system off?

#3 10-04-2004, 12:53 PM

I can turn it by hand without any hard resistance...is that good or bad?

BrierS · #4 10-04-2004, 01:13 PM

Quote:

Originally Posted by greggyc

I can turn it by hand without any hard resistance...is that good or bad?

We are discussing the A/C compressor . . . I have always read the first thing to check is belt tension. There is a tensioner at the front of the engine slightly to the left (driver's side). You mentioned some black debris? Does it happen to be belt particles? Do you see any cracks or other signs of belt wear? If not, you could loosen the upper through bolt on the belt tensioner. The bolt head should be at the back and the nut at the front. It passes through a portion of the aluminum head casting. At the right side of the belt tensioner (left as viewed looking into the engine compartment from the front of the vehicle) is a hole that you use to apply some tension on the tensioner as you loosen the bolt. I typically use one of my 3/8" drive extensions in the hole to put enough pressure to relieve the tension on the bolt. Once loosened, work the tensioner some with the 3/8" extension. Hold pressure and retighten the bolt. Snug is good . . . if the belt is worn to a point that it needs replacement, this is the same procedure you will use. If in doubt, replace the belt.

There are many members that have much more experience with these. I have attempted to touch on the simple items.

psfred · #5 10-04-2004, 10:43 PM

Inspect belt for damage. All ribs must be complete, no cracks across, no missing bits, not signs of shredding.

This will be a huge PITA on the 190 2.6, as the belt is pretty much under the radiator support.

If the front part of the clutch spins more or less freely, it's not locked up, the belt is slipping.

Very likely the tensioner is shot, but the only real way to check it is to release the belt tension and verify that the pointer on the housing moves back to the start position. If not, remove and inspect, likely you will find the rubber torn, meaning the "spring" is gone.

If it's been slipping, the belt will be a mess, replace it and the tensioner.

Peter

#6 10-05-2004, 01:06 AM

My belt is perfect. No fraying, no shiny spots, no cracks, it's tight. I can't turn the compressor pulley by hand...but I can turn the inside part that engages and starts turning when the button is pushed. The belt isn't slipping. There are pieces of black stuff in the direct vicinity of the compressor...but it isn't belt material...it looks like greasy pieces of soot that came out of my VW TDI intake when the EGR was cleaned...but the belt is totally intact...I watched the compressor try to start yesterday...the outer pulley didn't even slow down when it engaged...but the inner part barely turned. Either the compressor is trying to lock up or the clutch is not holding the compressor tight enough to compress.

#7 10-05-2004, 01:08 AM

you asked me if the outer portion of the pulley will turn with the engine off...no it will not....I turned the inner part freely without any major resistance...misunderstanding

raylee · #8 10-05-2004, 01:25 AM

if you have a harrison compressor looks like earley model GM.compressor about 12 inches long check the center of the shoe the one that starts to spin when compressor is engaged the shoe center is rubber and brakes away make sure the center nut spin's at the same rate. next check voltage to your field coil ti need's 12 volts

#9 10-05-2004, 05:20 PM

I'm pretty sure it's a Nippon/Denso...it looks nothing like the Harrison on my '86 Chevy truck.

psfred · #10 10-05-2004, 07:16 PM

I've seen this before -- leaking front seal causes the rubber insert to fail, so that the outer ring of the clutck that actually contact the pulley isn't connected to the inner part that turns the shaft.

You will need a new clutch and to replace the seal. This can be done in the vehicle with the proper tools (pin wrench to hold the clutch, although if it's torn, you will have to find something else) and the tools to R&R the seals.

Or you can pull the compressor, take the front section off, and replace that o-ring and drive the seals out and new ones back in.

This isn't difficult.

The black stuff is the rubber in the clutch.

Peter