A/C clogged expansion valve? (1 Viewer)

[RhinoRig]

Hey all,
I swapped out all the o-rings and swapped to 134a. The A/C is fully charged and but not blowing cold consistently. I put a manifold gauge set on it and the low side is almost drawing a vacuum and about 200psi on the high side, so coolant isn't flowing. FSM says it could be moisture in the system or the expansion valve is clogged, which is a bitch to get at. The manual says there could be dirt in the valve and to just blow it out. I can get a new one locally if needed. The only down side is that it's very difficult to access the valve and I want to make sure that is the correct course of action before opening that can of worms. Any one have experience with this?
Thanks!

 

[aztoyman]

When you swapped to 134A what all did you do? It's more involved than changing seals and the refrigerant. Shouldn't have moisture if you pulled a vacuum.

Was it cooling well before the swap?

No matter what, it needs a clean, dry system with the proper type and amount of oil. The evaporator may be dirt plugged externally if it's original. EVERY one I've ever seen that is original typically looks like a dirt brick. I'm in dusty Arizona though.

The current replacement parts should be 134A compatible.

If you have a clean evaporator, new expansion valve, new dryer, clean lines and condenser, a functioning compressor with the correct type and amount of oil you should be fine for years. Other than topping off a charge. The electrical side has to be in working order obviously.

 

[RhinoRig]

Thanks @aztoyman
I had the evap out and yes, it was filthy. I should have replaced the expansion valve while it was out. The PO said it was working, but I suspect he swapped compressors, so no idea. I should pull it, drain and replace the oil. Guess I’m going back into the dash to replace the expansion valve.

 

[aztoyman]

Yeah that sucks that you have to pull it apart again. On the positive side, the electrical part of the system and the compressor seem to be working. Now you just have to make sure it's all clean, evacuate, charge and enjoy the cold air. I would replace the dryer too if you haven't already. Good luck and let us all know how it goes.