I have no coolant flow through the heater core when the AC is on/heater off.

Verify the compressor RPM. With the diesel engine's narrow operating range, swapping engines & compressors can lead to a mismatch. A compressor that is too small or spinning too slowly will give poor cooling. The OEM compressor for your truck was a 210 cc/rev York type compressor. If you instal...

What suggestions has your parts supplier mentioned. As to not go over things already discussed? I haven't talked to anyone about it except on this forum. It's relatively cold here so I am waiting for it to warm up some to get some pressures and temperatures. It does put off a lot of condensation. I...

The only thing factory is the evaporator, which was thoroughly flushed out multiple times with commercial solvent and pressurized flush system. I don't have the factory oil specs, as it was R12 so I didn't look into that. Yes, brand new universal R-134a drier was placed in the system. Here is a quic...

We charged it by pressure if I remember correctly.

I believe the compressor came pre-charged with oil, but I did buy Sanden SP-15/PAG oil for it, so if we had to use oil that is what we used.

I will have to check the pressures and get back with that info.

I have a 1977 Ford F250 with a Cummins Diesel swap. It is a factory AC truck. When I did the swap, I flushed out the factory evaporator several times, bought a new Sanden SD7H15 compressor, expansion valve, and largest parallel flow condenser I could fit in the front of the truck. I also put a new f...