frebor72

I have a grinding noise that appears after some time. Like 30 minutes or so. If a turn the ac off the grinding stops. I have also found some metal shavings on the outside of the ac clutch. And the clutch gap is a bit wide.

Is it possible that it is the clutch and not the compressor? Compressor is quite new but the clutch is old.

Aaron R.

I had a grinding/vibration a/c issue with both of my Camaros.

On the 1987 TPI it turned out to be insufficient airflow across the condenser. The twin factory fans were not coming on frequently enough to keep the condenser cool. High cooling system pressures were causing a LOT of vibration at the compressor. At first I tried to fix it by using an old TSB to fabricate an additional support bracket. Didn't make any difference so I investigated more and found the lack of airflow/high pressure was the issue. I already had a Dakota Digital fan controller on it, so I just wired it to run the fans anytime the a/c was on. As a bonus, the a/c blew much colder at low speeds too.

On the 1985 carbed it turned out to be insufficient airflow across radiator AND idle too low with a/c on. This car also had a Dakota Digital fan controller so I wired that up like other car, then fabricated a bracket and used a NOS high idle solenoid off a 1980's quadrajet (Ebay about $15). I made the bracket to fit the high idle solenoid by the carburetor (Edelbrock) throttle lever and wired the solenoid to activate with a/c on. This fixed my vibration/grinding issue and also gave me cooler a/c temps at low speed.

Your issue might be same as above, or could also be the clutch. I'm skeptical the clutch is the issue though, because if it works fine for first 30 minutes this indicates to me it's more likely to be an issue with heat/pressure gradually becoming too high in the system and straining the compressor as it builds. Checking your clutch gap is easy and only requires a feeler gauge set ($5-$10 at local auto parts). Do a Google search with keywords "a/c clutch gap" and you will find tons of how-to videos.

sofakingdom

iTrader: (1)

Let me guess: "shop"? "Mechanic"?

I know you can't reach back into the past and change it; but it never ceases to amaze me how "shop" bends people over on antique cars. Not that they necessarily intend to defraud, or otherwise act unethically; just, poor decision making. In the case of an ANTIQUE AC compressor, it makes NO SENSE WHATSOEVER to do what this person did, for EXACTLY this reason. If the compressor decided it was time for its spirit to go to compressor heaven, the clutch that's on it has EXACTLY the same amount of use for EXACTLY the same length of time under EXACTLY the same conditions and is therefore in EXACTLY the same state of decrepitude, and needs to be replaced EXACTLY as urgently. This is NOT the same thing as working on a newer car, where a part can just randomly fail even though not worn out, and you can change out JUST THAT ONE part and be OK. ANTIQUE cars are not like that.

Just replace the whole compressor and be done with it. Mark my words, if you try to cheeeeep out and just change the clutch, the compressor won't last a whole season. Sorry, that's just the way of the world.

And this time, and all times forever more, don't bother with "shop" and "mechanic".

Aaron R.

I'm not a fan of just throwing parts at a problem, especially if the parts cost $100+ (like compressors). I recommend you troubleshoot a little bit first, it might be an easy fix or something you haven't checked besides the compressor.

Make sure you have a fan (engine driven or electric) constantly moving air across the condenser (located in front of radiator). Make sure there are no obstructions (dirt, leaves etc) between the condenser and radiator. Make sure you have an air dam in place beneath the car (use search function if you need help with that). Check the clutch gap with a guage. It does not have to be removed from the car to check it.

sofakingdom

iTrader: (1)

Air dams and whatnot will not cause an AC clutch to shed metal shavings.

The clutch is EFFED UP. No amount of checking will put the metal chips back and make it whole again. It needs a clutch AT THE BARE MINIMUM. It SHOULD have been changed at the same time as the compressor was. That was just BLATANTLY POOR decision-making on the part of "shop", which led DIRECTLY to this EASILY PREVENTABLE failure, and is why "shop" is NOT a reasonable option for someone trying to drive around an ANTIQUE car. "Shop" basically charged you EXTRA LABOR and in the process EFFED YOU OVER while lining their pockets. They SHOULD HAVE sold you the part and not dinked around with putting an old wore-out million-mile ANTIQUE clutch onto a brand-new compressor. That's just pure BONEHEADEDNESS.

Note that I am NOT saying "your air dam is fine"; NOT saying "don't bother checking for obstructions"; NOT saying "the clutch gap is fine"; NOT NOT NOT NOT NOT NOT NOT. All I'm saying is, NONE of that matters to the issue at hand, of the clutch making noise and shedding metal chips.

Aaron R.

Frebor,
I haven't seen any picture of these metal chips so I'm not going to jump to a mechanical conclusion or pretend I can diagnose your car with 100% accuracy over the internet. Keep in mind if your A/C clutch is being overloaded with high pressure/heat it would induce extra strain on the clutch itself as it cycles on/off and there will be excessive shedding from the clutch, so I recommend you diagnose the issue before throwing parts at it. The clutch IS designed such that it will wear gradually, and a very small amount of shedding buildup is normal, especially if you don't wash the engine regularly. If you have a condition accelerating this wear there could be an unusual amount of shaving buildup. It is possible your clutch is going bad, and it is equally possible that you have a separate problem straining the clutch and causing some shavings.

OR,

Go ahead and follow the advice of an internet "mechanic" who has already figured out what is wrong with your car. He actually could be right, so go ahead and buy that new compressor (about $175, depending on where you shop and whether you buy used/new) and throw it at your car. If that mechanic turns out to be wrong I'm sure he will reimburse you for the cost of that compressor and he will be happy to offer more expert mechanic advice. It's win/win!

frebor72

Thanks for the replies!

Itīs probably normal wear on the clutch. The only reason that I considered only to replace the clutch is that when my compressor was replaced by a shop here in sweden we couldnīt find the right compressor. But we found a new one to a van but it had a different pulley. So the shop replaced the compressor but reused the pulley and the clutch. So the compressor is new but the clutch is old.

But after reading your suggestions I will start with checking the fan and the condensor. If I donīt find the information I need regarding fan control I get back to you. Once again thanks!

MarksmanB

Hey! I hate to revive this thread but im having the same exact issue that you mentioned. I installed a brand new compressor and pulley/clutch and here i am 3 months later and its grinding and getting real hot and smoking and throwing shavings everywhere. So im wondering if you ever found out a cause of solution? I cant find anyone else on the internet that have a problem like this. Thanks!

sofakingdom

iTrader: (1)

Se posts #3 & #5. Details may vary but the basic content is the same.

Your compressor is bad (has internal parts binding or otherwise not running smoothly) and has destroyed the clutch (converted it to metal shavings).

I hate to be the bearer of bad news but It Is What It Is. Recover the refrigerant; flush the lines, condenser, and evaporator thoroughly; replace the compressor, accumulator/dryer, and orifice tube, putting about half the new oil in the compressor and the other half in the new accum/dryer; evacuate; recharge. If it hasn't already been converted to modern refrigerant of some sort, now is the time. Search this forum for my userID and the phrase "orifice tube" for detailed instructions and parts recommendations.

Aaron R.

Or if you don't like throwing parts at a problem you could diagnose it with posts #2 and #4 above. "Getting real hot and smoking" could be excess pressure/heat and the high pressure release valve activating (blowing excess coolant pressure out, sometimes appearing like smoke).
Throwing parts at it MIGHT solve it. The OP lives in Sweden though and that was definitely not a cost effective option for him.