A/C expansion valve

[Bob Barron #15075]

Is the expansion valve for the 58 Cadillac interchangeable with another Caddy year, or other GM car expansion valve? I heard possible the 57 Caddy is the same, but no one knows for sure, let me know thanks. BOB

[Ed Mobley]

FWIW, I ordered an expansion valve for my 60 Caddy from Old Air products.  The valve I received has different dimensions than the original and is of different construction.  I called them up, and they said I had the right valve.  Im wondering if they chose one that was "close enough" in which case you could do the same for your 58.

After doing some research, picking the right expansion valve involves getting the correct superheat ajustment for the evaporator.  Unfortunately, most auto a/c expansion valves can only be adjusted when they are removed from the system - something that is not practical unless you have a way to recover the refrigerant - even at current prices, R-134 is worth recovering.

Im wondering if they make an externally adjustable expansion valve for auto a/c application.  Is so, I could adjust it to get the right superheat without having to evacuate the system.