AC System Service Questions

[RCWD21]

When I get my pathfinder back on the road I plan on properly converting the AC system over to R-134a refrigerant and fix the few small leaks I've discovered due to old and aged orings.

 

The local shop will be doing the evacuation seeing as I'm not sure if there is a mix of R12 and 134a in the system. After that I plan on buying my own vacuum pump and manifold gauge set.

 

Now down to the specifics that I want to double check.

 

Seeing as I'm using a compressor that was used in an r12 system would I use mineral oil even with the 134a refrigerant or would I empty out the compressor as best as possible and switch it over to PAG 46 oil? I know there is a viscosity difference between PAG 46 and 100.

 

When I look on Rockauto the compressors state to be used with PAG 46 so am I right in assuming that I need to use PAG 46 when I convert over?

 

Also is the refrigerant and oil capacity the same between an 87 R12 system and a 95 r134a system?

 

I believe the refrigerant capacity for the r12 system calls for 1.65-1.87 pounds at 85 psi or higher and the oil capacity is 8.6oz of Suniso 5GS oil which is obviously what was used from the factory but the new oil is a PAG oil.

 

I know this is a long post but I'd rather do this myself as the local shops don't really do the best ac work and I'd feel much more comfortable with knowing I did it properly and that I won't have to keep taking it back for the same issues.

 

Sent from inside my potato