Sorry you didn't receive an immediate reply. I've been thinking on this for a little while. I believe bohica nailed it, though. I can't say for sure 'exactly' where the oil went, but it does sound as though the compressor ran completely dry and ground itself into oblivion. The material from the comp...

I've never worked on a CAT Challenger. Nevertheless, mobile A/C theory is essentially the same regardless of vehicle, so I'll jump in with some questions. I have replaced compressor, accumulator, orifice tube - flushed out complete system - new thermostatic switch and low pressure cycling switch... ...

Did you accidentally post to the wrong thread? This one began with an '87 Chevy truck and you're talking about a '99 Cadillac DeVille. I'm confused.

As for the orifice tube, the long screened part should point toward the condenser, not the evaporator.

The POA Update Kit replaces the POA valve with what amounts to a straight-through tube and a pressure switch, which is calibrated to turn the compressor clutch on and off to prevent evaporator icing. The original POA valve regulates evaporator pressure by means of internal valving to prevent evapora...

Did the compressor seize when you began having trouble with it?

The pressures you originally posted--about 130 PSI on the low side and 150 PSI on the high side--are they static pressures (system turned off and compressor not running) or are they the pressures you get with the system and compressor running?

Before delving into it more deeply, check the simple stuff first. Ensure that your quick-connect port adapters are opening the vehicle's Shrader valves fully. If you have the type of adapters with the red and blue thumbwheels, turn both thumbwheels fully CLOCKWISE to open the Shrader valves. Next, w...

Since you pretty much looked at everything else, I, too, was about to suggest that you take a closer look at that POA valve. But you already discovered a latent problem with it. Great! After all your work on this system, I hope that the rebuilder will at least send you another POA at no additional c...

Although conversions don't cool as well as the original R-12 and the R-134a charge might still be a little low, with pressures like those, you should be getting some amount of cooling, not 80-degree air. It sounds to me like a lot of heat is mixing in someplace. With a vehicle that old, the blend-do...

Sorry.... Not "read" the engine..... It should have said "when I rev up the engine" auto correct turned rev into read. Got it. Happens to me as well :lol: I don't know what a CCOT or a TVX system is. Clutch Cycling Orifice Tube, or Thermostatic Expansion Valve I welded the hole ...