Replace Evap Core/liquid hard line?

[Jak22099]

I'm doing an r134a conversion on my '84 k10 with factory AC, getting a new parallel flow condenser, new compressor, new manifold hoses designed for r134a, and of course a new accumulator and orifice tube. My question is... can I get away with leaving the evaporator core? I really don't want to go to the trouble of taking it out if I don't have to. Would I be fine just flushing it out and hooking everything else up? The engine was swapped and after the new one was put in the hoses were left off for awhile so it has been open. Same question for the hard line that goes from the bottom of the evaporator core to the bottom of the condenser... do y'all think this could also be reused as long as I replace the o-rings?

Thanks for the help!

 

[fast 99]

Hard line and core will work with 134. new orifice o rings and flush as you describe

 

[Bextreme04]

When I did mine, I replaced the O-rings everywhere, the manifold and lines from the compressor, the filter/dryer, the pressure switch and the orifice tube. I still have the original factory condenser, evaporator, and A6 compressor installed running PAG 150 and R134.

 

[fast 99]

When I did mine, I replaced the O-rings everywhere, the manifold and lines from the compressor, the filter/dryer, the pressure switch and the orifice tube. I still have the original factory condenser, evaporator, and A6 compressor installed running PAG 150 and R134.

Yes, that is required. 134 molecule is smaller than 12. 134 will leak through 12 O-rings.

Another way to look at these conversions is the general 20% rule. Molecule is 20% smaller, pressures are 20% higher and cooling is 20% less. If 134 was a superior refrigerant, manufacturers would have used it, not 12.