Air Conditioning troubleshoot high side normal, but the low side is too high - too much charge The expansion valve is the same as used on Ford Falcons and Mustangs of the 60's. When I was troubleshooting my system, the valve was suspect. NAPA no longer has the original type. I searched and searched and no one else that I contacted has any of them in stock. It's a straight through valve with flared ends. Most anything in air conditioning that uses flared couplers is hard to find anymore - everything is O-rings today and has been for the last 25 years. The last air guy that I worked with said a more modern valve could be adapted with some custom hose making if it does ever fail. Mine was OK, for now. If you do find a source for these expansion valves, please let us know. The condition you have now could also be caused by some other type of restriction, like a plugged receiver/dryer. NAPA 904-272 for 65-66 Mustang. It's a 3/8 male flare 1/2 inch male flare right angle valve, The Delco number is 15-534 or 15-540. It's actual application (I shot from the hip again) is the 1966-67 Ford Fairlane. Remembering my conversation at the NAPA counter (risky - ha ha), we also traced this number to 62-64 Falcons and 64 1/2 Mustang. The valve is straight through and as I recall the flare that mounts toward the evaporator is 3/8", and the one that mounts toward the condenser is 1/2. (D.D.'s Technical Tip book is source of Delco Numbers and an illustration). I found a straight 3/8 to 1/2 flare listed for 66-67 Falcon/Comet and 67-68 Mustang If you replaced your dryer this winter, did you recharge with R12 or R134a? If you recharged with R134a, it's about 80% efficient when compared to R12. Also, the desiccant in older R12 dryers doesn't work well with R134a. bought my car in April of '98, the air was ion. Seller told me that compressor had a small leak. He had included a new York compressor with the car. I had the system charged, and sure enough the first season it worked fine. I decided to have the compressor replaced next season. When I had that done, they young technician put everything together and couldn't get the system to take a charge. He thought the expansion valve was stuck closed. I spent the summer of '99 without air and searching for parts. Next spring, I located a guy who had been in the business since the 1960's. I took the car to him with the closest parts I had found and told him to do whatever it took. He called me back in about two hours, saying it was fixed. York made compressors with right port suction and left port suction. The replacement compressor was opposite of stock. The first guy had the system hooked backwards! He simply switched hoses on the compressor, and it worked fine. York did not mark the ports on the compressor with any outward indication. The only way to tell is the part number on the box. Something to keep in mind when searching for original type parts! I kept the system R12 despite the sales pitch of the first technician.