Yesterday I discovered that my high side service port for the AC was leaking. Apparently this is a real common issue on the GM trucks and SUVs. The port doesn't use a schrader valve like most cars. It uses a design unique to GM. I went to O'rileys for the new part and the parts guy didn't have a clue what I was talking about. I went home and found it at NAPA, ordered on-line and went to pick it up. It's an easy job but, what appears to be a 5/8 nut(ish) isn't. It has a line through it that makes you think it will come apart. It won't. Look at the replacement part real close before you start twisting on it or you could easily damage the AC line. I was able to get the old part out and the new part in quickly. Normally it takes a special 8 sided socket that I didn't have. I used pliers and was careful not to scratch up the sealing surfaces so I could connect to the high side and get a seal. I added an ounce of PAG oil because I lost a little in the process. Probably not an ounce but whatev's. Now no leak and I kept the box from NAPA so that if I have to do this again in the future I'll have the part number ready to go. Much easier job than I expected.

 

what year vehicle and what type of refrigerant? do you have a hybrid? post a pic?

r134a fittings are not a gm thing. Its industry wide since 1995.

 

AcDelco part number 15-5438. This port does not have a shrader valve. It has something like a ball valve and cannot be repaired. The whole thing must be replaced. The system is R134a in a 2000 Suburban. Seems to be fixed now. At NAPA it was a shade over $5 bucks. Really easy fix as long as you have the tools to draw down and refill the system.

 

that is listed as a pressure relief valve. the systems are filled through service port couplers which are completely different.

 

Whatever it was it's fixed now and apparently a very common issue on the 5.3 engine GM vehicles.