Hi again:

My father in law (who is an experienced A/C guy) is flummoxed with my 87 240. Instead of charging the system with R12, we thought it best to go ahead and begin with 134A. He converted my A/C from R12 to R134A by evacuating the system, and recharging with 134A. There were no leaks but the system didn't seem to cool well. He cleaned the condensor & radiator. He replaced the accumulator & the expansion valve. The system would cool but would not reach a temperature of under 67° at the vent. He then reduced the amount of R134A in the system which brought the temperature down some. The main problem seems to be that it won't cool at an idle much below 68°; however, on the road it will drop to about 52°. The compressor seems to be working (probably not like a new one, but he has no indication the compressor is malfunctioning). Head pressure on the compressor is in the 200-250 range. Revacuumed the system again today, and pulled it down to 30 vacuum, and left for 30-45 minutes and it held.

Could the evaporator core is dirty? We didn't change the oil in the compressor, but added 2oz. According to his information, at 30lbs. it should have a temperature of about 38 degrees. Can anyone suggest some other items to check?

Any suggestions would be helpful!

Thanks,

Andrew in NC