I have a 1991 Firebird. The A/C would not a hold a full charge for more than a day. I decided to replace the R12 with R134a components thinking any leaks might be fixed. I changed out the compressor, dryer, hoses and orphice tube with new ones. Took it to a shop today and they pulled a vacuum on the system and it held tight so they charged the system. It was working well for not even 12 hours and the clutch started engaging every few seconds and the air was no longer as cold. I believe this is an indication the freon is low.

How can you tell if the evaparator is leaking? Would a vacuum determine a leak if there was one in the evaporator. Also would this be the case for the condensor as well?

Any ideas?

 

Did you add the oil treatment can? Is it blowing good air? Just not cold?

 

Yes I did add the oil as recommended. It was blowing good cold air and throughout the day it decreased in coldness and the clutch began to constantly engage.

I figured with a leak that large it would not hold a vacuum.

 

Get the shop to use a 'sniffer' or have them add dye so that the leak can be seen with a UV light. You might also consider the condenser as the leak source.

JamesC

 

Just got back from the shop. The compressor seals for the hoses that came with the new compressor were not thick enough. When newly installed the thinner seals were good enough for the vacuum but once high pressure and heat was a factor the seals gave way causing a good size leak. Replaced seals with thicker ones and it seems to be fine for now, no leaks detected.