I have taken my AC down and had the compressor rebuilt and resealed and put a new dryer on. When I put the vacuum pump on it there was no problem holding 30 lbs. of vacuum, but when I started charging the system, after adding 4 oz. oil, my low side would not come down below 65-70 lbs., even though the high side went up to 250-275 like it should. The car doesn't cool very well at all and I suspect that I have a defective expansion valve.
Can anyone verify this to be the case, or let me know where else to look for the problem.
Thanks in advance.