I have a 1989 740 turbo that has had the AC converted over to R134. The conversion was done 2 years ago by a Volvo shop with a factory conversion kit I live in the Phoenix area and have no AC!( its now 100 degrees). I have taken the car in two times to a national car repair shop. They found no leeks. First time, they added dye and Freon and said the compressor showed signs of leaking oil but everything check out fine pressure, volt wise. The air was cool on fan setting one but warmed up as the fan speed was increased. My second trip 3 weeks after the first, they still do not see any leeks but added more Freon. They asked me to take the car and see what happens. I purchased the car from my Dad who had the AC conversion done and the AC was ice cold. What should I check to improve the performance of the AC. Should I replace the compressor? Dose any one know of a good AC shop in Phoenix to get a second opinion?