A/C screeching when clutch engages

[Jack Parl]

Just inherited a complete

ly stock 82 sport coupe .A/C didn't work, local shop filled it with r134 . Two weeks later , identfied new screeching noise only when A/C clutch is engaged . ( cycles off , no noise) ANY ideas guys ? (Was going to ask Petty , don't think he ran with A/C) lol

 

[buickruss]

Same scenario for me. I can get a rebuilt compressor $135 and receiver/dryer for $40.
Or try to replace the clutch on for about $60.I found the loaner tool at the local autoparts store

 

[SuperSix]

Sounds silly, but check to make sure the belt isn't glazed and slipping. It may look fine, but slip under load.

 

[Jack Parl]

Thanks for your input! Any one else want to add a solution? Read other forums ,
someone mentioned that a system low on 134R can cause simular noise, this V/6 turbo had been filled with 12R previously. ( I think its the original compressor)

 

[SuperSix]

Low freon will make the clutch cycle frequently, not "screech".

Assuming the A/C shop did the retrofit the right way, (replaced dryer/accumulator, flushed all lines, changed all orings, added correct type/amount of oil and freon charge) some things it may be:
Compressor is seizing/failing and dragging on the belt
Clutch plates are out of adjustment/frozen/dirty/contaminated/etc
Clutch solenoid isn't getting full 12V so the solenoid coil doesn't get enough juice, so the magnetic pull is weak (This one is a pure guess)

 

[charlief1]

moved this to the general section so you'll get more help. Does the clutch make noise if the AC is running at idle or while you're driving? Like Mark said, it could be a loose or glazed belt. What you may have happening is the clutch is worn to the point that it doesn't grab enough. Easiest way to check this is to use a set of brass feeler gauges to see what the clearance between the clutch is. If I remember right it should be about .015-.020 but I may be off there since it's been a while since I looked it up.

 

[Jack Parl]

Thankyou Charlief1 & super6!
Compressor screechs when engaged , at idle or at speed.
All belts are new, Appear tight.
Can run with AC off but its hot out hear. Will test further. Want to be well versed in A/C repair before going to an A/C repair shop. ( have heard stories , some not so good) Thanks

 

[charlief1]

Take something and mark the hub in several locations. Do the same to the part of the compressor and run the AC while watching the clutch engage. If the clutch is slipping you will see the marks on the front stop and go while you won't easily see the hub marks. Should be like looking at something in a strobe light.

 

[turbojoes]

I had a problem like this before and just sprayed the clutch with wd40 and the screeching went away. Just dont spray it on the belt.

 

[Jack Parl]

Great ideas both ! Thanks guys, love this forum....