well, after putting up with noise coming from my compressor for a while now I decided to investigate the matter more closely.

3-4 of years ago I took it to a dealer to fix the noise and as I recall they sent me home $300 short and with an explanation that this was due to a noisy compressor pulley that they replaced.

well, I was ignorant about these things back then so i didn't bother to question them.

well as i am looking at my compressor now, the pulley does look new, however the pressure plate on the clutch is brown and with cracks. I measured the resistance of the field coil and it came up with 4.5 ohms (80F), instead of 3.6 +/- .15 ohms (68F).

i wasn't able to measure the clearance between the pulley and the pressure plate, because its sitting inside the pulley. But visually it looks close enough.

looks like clutch is slipping and generating heat and noise in the process.

the noise is worse when its hot outside, just when I need AC most.

any ideas?

 

Make sure there is around 13 volts or so at the field coil when the clutch is supposed to be engaged. If so, new clutch and pressure plate.

 

how do i check that?

 

Did you measure the resistance?
I guessed you had experience.
You need to set the voltmeter on volts, one lead on each of the wires to the clutch, or if it's only one wire, then the other voltmeter lead to a clean metal part on the engine (no paint). You might need to use a pin to get through the insulation to the copper wire. do that on the clutch side of the connector, if possible.

 

If clutch is engaging and slipping, it's probably not a clutch fault.

Try turning the clutch plate by hand (rotating compresssor by hand). It should turn easilly, w/ no gritty feeling, and only a slight resistance when compression of gas occurs. If you have trouble rotating by hand, or feel any grinding feedback, compressor is probably going to fail.

good luck

 

well, i measured the voltage.. 13.89 DC.. couldn't get a stable reading in AC mode.
the clutch turns with great resistance when turning by hand.. i don't feel any grinding.

is it possible to add some oil to it?
replacing compressor will be expensive, and if I do that will I have to replace condenser or flushing it will be sufficient?

 

Here's my guesses, but I'm not really an AC expert.
Someone that is, chime in!!
It could be that the clutch friction surface is worn down enough that is is slipping when engaged.
You might be able to replace the clutch assy, with the pulley, clutch, and coil and be OK.
That might not be much different $$ wise than replacing the entire compressor. If the compressor internals have gone bad and particles are throughout the system, you should probably replace the receiver/drier and flush the rest of the system.

 

The great difficulty to turn the clutch pressure plate by hand suggests the compressor internals are binding. Unless the pressure plate-pulley face gap is so tight you were trying to turn the compressor pulley also, the compressor is on it's way out.

No short cuts when you have a failing compressor. It has probably already shed some aluminum particles into the system. You will need a used or rebuilt compressor, flush and clean condensor, new receiver/drier, flush and clean all hoses, remove evaporator, flush and clean, remove expansion valve from evaporator and inspect for blockage and replace if necessary, replace all system orings, install new lubricant (~8oz) w/ new receiver/drier and compressor, close system, pull full vacuum & hold for 15 minutes, if no leaks vacuum for at least 1 hr, and charge w/ spec amount of R134a (23 oz).

I have found a used compressor to be an excellent value, usually < $100. I've never had a bad one. Best to check car-part.com for local salvage yards w/ your model, then visit and inspect the likely options.

Love to hear how your repair works.

good luck

 

I gave wrong refrigerant amount for your system. It should be 26.5 oz. Also lubricant amount should be closer ~9.5 oz.

good luck

 

thanks very much for the replies.
however, i'll have to wait on this one.