Quote:
Originally Posted by davepl
My truck is in for final tweaking (charge the AC, align the wheels, etc). The HVAC guy is coming in special to do my truck.
When I restored it, I used all brand new pump, condenser, and dryer. I put in all new o-rings. Whatever is in or on the firewall box is factory original still.
I drained most of the oil out of the compressor before installing it but I didn't flush anything. I vacuumed the system down to get moisture out while it sat waiting. The dryer says its compatible with both R-134 and R-12 (I guess they mean the dessicant inside is compatible).
Now: can I have it charged with R-134? Or do additional changes need to be made?
The mechanic (not the HVAC guy) said that you can still get and use R-12 on old vehicles but that it is very expensive. If that's true, perhaps that's the way to go if R-134 requires changes that I haven't yet made.
Is there a short answer on which way and how to proceed from this point to getting it charged and running?
Thanks!
Dave
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Technically it's the desiccant bag that is compatible. R134A destroyed the old bags and blew desiccant all through the system.
The expansion valve should be replaced with a unit tuned for R134A. An R12 will work, but it will not be as cold.
R12 expansion valve hold the low side to about 32 to 35 psig and an R134A unit will hold the low side to 20 to 28 psi depending on the type of pump.
The oil must be R134A compatible also. Ford uses PAG oil.