Need some AC advice/help EXP VALVE FIXED!!!!!!

It is important that the thermal bulb of the expansion valve is attached firmly and directly to the outlet line of the evaporator then wrapped in insulation. Without this, the expansion valve will think the evaporator outlet is warm and the valve will open wider to admit more refrigerant. High side pressure will drop, low side pressure will rise, and the compressor will slug with liquid refrigerant. You will eventually blow the compressor.

R12 and R134a expansion valves have a slightly different superheat setting but only slightly and not enough to cause this.

There is also the question of system charge amount. Even with a wide open expansion valve, there should not be any bubbles in the sights glass while the compressor is running. Charge amount does not effect the cooling effectiveness of expansion valve type A/C systems. All they care about is that there is enough refrigerant to keep the pickup tube in the receiver/dryer submerged in liquid refrigerant. Adding refrigerant just raises the liquid level. Bubbles in the sight glass means the pickup tube is not submerged, so you add refrigerant until the bubbles disappear then add a little more to give it some reserve.

I figured that was it. Glad you got it fixed and thanks for reporting back. 

Mopar_guy wrote: 401MATCOUPE wrote: Did you change the expansion valve to something other then the original fittings?  I am not understanding the issue??? Back on page 2 "No OEM parts, everything is aftermarket. "

Did you change the expansion valve to something other then the original fittings?  I am not understanding the issue???

george w wrote: Using R-12 or R-134 and does it matter ? Shouldn't the usual AMC vendors have the proper valve ?

Well it could be defective, as it is a low cost item, that is a wee bugger to get to if all finished up. As for difference yes there is. But most are happy with original R12 valve. If your doing a whole new kit or upgrade, I suggest obtaining R134 valve if possible to swap out. It does make it cooler, as the system does not cycle as much.

It should cycle once every 2 minutes, but it depends on capacity and tempratures. Between once every minute or two is good. The less cycling the more efficient the system.