Mazda Repair: 92 Mazda Protege AC compressor clicking noise, r 134a, mazda protege

Question
Hello,

I'm converting a '92 Mazda Protege LX 1.8 DOHC to R-134A refrigerant.  The AC system was discharged by the previus owner and held a vacuum all night when I started working on it.  The compressor makes an even clicking or rattling noise at idle when I add refrigerant.  The noise stops when I shut off the AC.

The low side pressure goes up and does not change.  The line at the reciever drier gets very hot about the time my low-side guage reaches 180 PSI.  At this point I shut he car off and let the system cool.  I disconnected the AC lines at the filter drier I'd just installed and vented a bit of freon into the low-side port.  I got flow from both tube ends where I'd taken the lines apart.

1. Has the compressor gone bad?

2. Is the metering device (orfice or TX valve) plugged?

3. Where is the orfice tube, if the system has one.  The TX valve would be next to the evaporator, of course, and digging it out would probably bring tears to my eyes.

Thanks,

Charles Lipe

Answer
Hi Charlie thanks for asking
If the compressor is making that kind of noise with the AC on then the compressor is going to have to be replaced, but before you replace it, discharge the fron and remove a line right of the compressor and dump in about 2 ounces of pag oil, install the line again and refill. Just see if that helps ar all first. If not then replace the compressor.   180 PSI? on you low side is way to high.. With the AC turned off both the high and the low side should be around 100 PSI with the AC on  the low side should be between 20 and 40 PSI and the high side should be about 200 PSI, you may have an overfilled system. IF any vehicle has a TX valve they are usualy located on the fire wall in the engine compartment, you will see two AC lines going inside the vehicle and is it has a TX valve it will be inline with those lines. IF it doesnt have the TX valve then the orifice will be in one of those to lines going in the vehicle, Just look for a wide part in the line where the is a fitting to slide the orifce out of the line.
Good luck
Chris P