This may sound like a dumb question but I recently aquired a 84 XJ6 and I need to top off the freon. The only place I see to add it is the nipple near the rear of the compressor. I am hoping that is the "low" pressure side. Am I correct in assuming this?

 

yes is right at comp so is the high it takes r12 not 134

 

you need to make sure what type of refrigerant you have in the system, many of these cars have been converted to R134a, you don't want to mix refrigerants, it's potentially dangerous and it will ruin the a/c system components.

if you don't know what refrigerant is in the system, take it to a a/c shop to find out.

 

If you're in the US then R12 is difficult and very expensive to come by. I just converted mine when putting the AC back in service. I changed the expansion valve, receiver/drier, drained the oil, flushed the system and refilled with PAG oil and R134. Working pretty damn well, this isn't the first car I've converted, either. No, it's not as cold as R12 but it's cheap and easy to find, don't let the conversion horror stories scare you. If you find after re-charging that you have a leak that needs to be fixed and have to re-charge again and you're using r12 then God help your wallet.

 

R134a is definitely not worth the time and money; There are other alternative refrigerants like Freeze12 which are colder, especially if you live in a hot climate, and are compatible with the older a/c systems.