R22TECH, need advise on Compressor Failure

[GT911]

I put a large condenser in my Carrera tail, all new lines and my a/c has been freezing cold, well it stays at 39f and that’s close enough for me here in Houston. Parked the car last Friday working great, got in it Tuesday to go to work no a/c. Everything is working, clutch, blower fans, but no cold air. I figured I lost the refrigerant, R-134, but I couldn’t find any leaks, so I put the gauges on and found the system is still charged, but the pressure is the same on the high and low sides.

Compressor is not compressing.

It has a rotary compressor and I have another one I can replace it with, but what steps should I take? I know R22tech has stated that the R-134a will deteriorate the seals in the compressor and I wonder about the failure I experienced. Can the compressor simply be replaced and recharge the system or has the system been contaminated with debris from the compressor and require flushing? I suspect that since the failure occurred while the car was sitting it is seal failure, would this put debris in the system?

Where do I go from here?

TIA

[stormcrow]

Is the clutch on the compressor engaging? check to see if you are getting 12v to the coil on the compressor clutch. If the clutch is engaging, and the pressure remains the same, then you probably have a broken compressor shaft.

Did you change the oil when you converted to 134A? If you didn't the only thing that could happen is your seals would become mushy and leak.

Steve

[GT911]

Yes the clutch is engaging, and the shaft is turning, at least the end of it is.

I used a 4 cfm pump, for three hours to evacuate the system, then used a conversion kit by Castrol. One can w/ dye, oil, stop-leak, and 4 oz of R-134a, and two 12 oz cans of R-134a. My gauges are for the R-12 ports so I did not install the port adapters.

I was really pleased with the performance. The conversion kit is on clearance right now for $15 at Wal-Mart. So it is really cheap to dump the system, change compressers, and recharge. I would just hate to waste another compresser for the sake of cutting corners, and I am not excited about the possibility of flushing 40 feet of hoses either.

It really sucks for this to happen after I was able to get R-134a to actually work well in a P-car.

[R22tech]

Hmmm? Based on your description, it does sound like compressor failure. There are other variables though. Did you say you had another working compressor? If so, I would evacuate the system, pull a vacuum for about 30 minutes after installing the new compressor, then recharge. I would not use the "dye" additive or the "leak sealer" this time. Just put the R134a back in and add ester oil. If it still does the same thing it could be a failed txv, but I doubt it. It's hard to tell without seeing it-sorry. Hope this helps-let me know the results and I will continue to try and help the best I can.

[R22tech]

I just noticed you put 28 ounces of 134a in there. What year is your car and how exactly did you figure out how much to use? I only use manifold guages to tell me when a system is properly charged-maybe you put too much in? Maybe too little?

[GT911]

The car is an '81 SC. With a new expansion valve, dryer, hoses, original front condenser and working blower. I added a large, 16” X 28”, parallel flow condenser from an early ‘90s Camaro in the Carrera Tail.

I read the tech article on Griffth’s web site with the yellow SC that they converted to R-134a and (claimed) were able to get it to 33f. They added a condenser in the left rear wheel well to increase condenser area, I figured that the larger condenser placed in the wind stream would have the same favorable effect, and it did. In their article they used 26 oz. of R-134a, and said it was optimal. The system basically took all that I fed it, so I’m pretty sure that it has between 27 & 28 ozs.

The compressor is a Hitichi model MJS170 6AA. Both of the compressors last had R-12 in them.

My ultimate dream is that the compressor that died was not 100% and when I replace it, the other will work even better.

Well this is my thinking, and my actions up to date. The only thing I have left to add is a high pressure cut off.

[Roland Kunz]

Hello

If your compressor runs can you feel a difference in hot and cool side temperature ?

Did you renew the dryer with a newer X-type fillment unit ?

The PAG oils must be "caped" and even then they eat up the Viton based seals.

Most AC suplieres can detect the used seals by identifying the compressor type#

Have your other compressor checked or convertet to PAG before you install it.

Grüsse