jasone36

Hello,

I have a high-mileage (130K+) 2002 SC430. My air conditioning typically works well, but sometimes if I turn the AC on when engine is not warmed up, the AC causes the car to make an un-natural loud grinding noise and almost violently shakes the entire car.

If I start driving in this situation it does not seem to make a difference, the car continues to shake somewhat violently when in motion (along with the loud sound from the engine).

To remedy this, I turn the AC off, drive for a little bit, then turn it back on... and BINGO, the engine is as silent as ever (except for a faint squeaking sound which seems to be always present when AC is on, barely noticeable).

Being a convertible, I rarely turn the AC on, but when I do it blows cold as it should. I recently replaced both engine mounts and the transmission mount on this SC430, so I figure the car shouldn't be shaking so bad, something unnatural must be going on.

If anyone has any thoughts on what this could be I would very much appreciate it.

Harold57

Is it a grinding or squealing noise (like a belt slipping)?

jasone36

Harold,

The primary issue is the grinding noise (almost sounds like an air compressor which is having a tough time keeping up with a load).

I also have a very faint squealing noise when the AC is on, but that has always been present and there are no other accompanying issues with the squealing noise.

Any help is appreciated,

mrblister

Check Serpentine Belt , Tension pulley, air cond clutch .

husker741

I had a similar noise on my old GS400 with over 170,000 miles. I think it turned out to be the air compressor belt. Every time I would have the air conditioning on, with the A/C (air compressor) button on, I would have a similar noise, but then I would turn the air compressor off, with the air still blowing, the noise would go away. The air compressor is the thing that takes away the humidity and musty smell from the air being blown around the car.

vicsis250

check you belt mine did that noise when it was cold

SDubz

I’m recently having the same issue with my SC and just tested what Husker said, and turning off the A/C stops the noise and shaking, so I guess it’s the air compressor belt that’s going to get changed out now.

dwoods801

It’s the clutch malfunctioning in the compressor, u can find them and replace them separately but it costs about the same as a whole remanufactured compressor, so might as well do it right, you’ll need to do the condenser and the valve that’s mounted on the firewall inside the cab, where the Freon lines pass through.

Cinc04

I went out and looked at my car and it looks like there is quite a bit of room in front of the AC compressor. Can the clutch be removed from the compressor while the compressor remains in the car?

The clutch is a relatively low-dollar item. A compressor is costly. In addition, if you remove the compressor you will have to evacuate the system, recharge, etc. Something that a DIYer can't do.

dwoods801

[QUOTE=Cinc04;11194836]I went out and looked at my car and it looks like there is quite a bit of room in front of the AC compressor. Can the clutch be removed from the compressor while the compressor remains in the car?

I think the style of puller will have room to do it's thing. But I think u would still have to open the system and you'll need to flush the lines out to get any debris from the clutch coming apart. So it's probably easier to just remove the compressor and my car had this exact problem, i did a lot of research before starting and everything went pretty smooth. I found a kit that came with a remanufactured Denso compressor, the valve, condememsor, solvent to flush the system with, and new o-rings and PAG oil. Everything said the condenser had to be replaced, but once I got it out, I realized that you just need to replace the dryer that's built into the end of it's once the old one dryer is out, the condenser is easy to flush it out and just replace the dryer. Separately the condenser is about $75 but it was only about $40 in the kit. Your supposed to unhook a valve on the firewall and flush the evaporator from there but it wasn't practical to do it on my car. And I didn't see how any thing could have gotten past the valve anyway, it would get trapped in the valve which is why it has to be replaced. And it was difficult to work on with the dash in place, but much easier than removing the dash. Once I replaced everything and put it back together, I rented a vacuum pump fr room AutoZone and evacuated the system, and made sure it was all air tight. Then hooked up some R-42 I bought off eBay, it is a very efficient refrigerant that is compatible with both R134 and R12, only it works better than either of them. Now my A/C can make the can of my car below 32 degrees on an 80 degree day. So it's like driving around in a freezer if I put it on max. I got OEM components for about$500 and did the work over a weekend. A new aftermarket kit was available for about$400 but I always prefer OEM

Wilson2000

[QUOTE=dwoods801;11194853]I agreed with your post and commend you for tackling your AC repair yourself, but I question the quote above. Isn't the clutch on the outside of the compressor? Could clutch debris even enter the closed refrigerant system?

dwoods801

[QUOTE=Wilson2000;11195336]you know that sounds like how you would think but when I looked into doing just the clutch I recall being warned that there would be debris in the refrigerant and that was part of why I decided to replace the compressor, but I never actually dissected my old compressor to see how it was setup, and also I never found any debris while flushing the lines. The solvent was part of the package I bought and the warranty required it to be flushed, so nothing would end up inside of the new compressor and destroy it. I am assuming that must be something they look at before issuing a replacement on a warranty claim. You might want to see what you can find out before making any decisions. I also decided to replace the entire compressor just out of fear it would have bearing or compression problems in the near future. My original one was at about 150,000 miles when it started making that noise. I have a friend who specializes in home hvac systems and is pretty knowledgeable with automotive ones also, and he advised me that the clutch would be the source of the noise I was hearing, and also that it wasn’t the only issue the compressor could have. So I just followed what he said. I will have to ask him how/if the clutch is wet and would be the source of any potential debris. Thinking about it now, especially after not finding anything, it seems the more likely cause of any potential debris would more likely be an internal source. I also remember he was confident the noise was from the clutch because it still worked fine otherwise. If it was something internal, like in the rotating assembly, it wouldn’t cycle right and wouldn’t work anymore. I will get a hold of him today and let you know what I find out.

iolmaster

iTrader: (1)

[QUOTE=Wilson2000;11195336]I have never taken apart a compressor on an SC but I have on other cars and you are correct. The clutch is not something that could get into the refrigerant line. It is on the outside.