AC oil & 134 capacity question

The AC compressor went out on my daughters 91 Explorer 4.0. I bought a new (rebuilt) compressor, filter/drier, and orifice valve. I read and searched until early this morning but I can't seem to find the type and amount of oil I need or the amount of refrigerant I need. From the sounds of Glaciers sticky I will need to get new hoses and do some flushing too. There is a LOT of very good information in the sticky parts especially for someone new-me- to air conditioning. I am glad I read the safety things first. If you need more information I might be able to provide it. Thank you.

The 91 Explorer came with R12 as the refrigerant. If you can find it, you will need 1.75 lb (32 oz) of R12 and 7 0z of air conditioning mineral oil.

If you intend to convert to R134, flush the condensor, evaporator and hoses. Check the orifice in your system. If its coated with black gunk, it's recommended to change the condensor also. It's not necessary to change the hoses unless damaged.

With R134 use 7 oz of PAG 100 oil. 3 oz in compressor, 2 oz in accumulator (drier) and 2 oz in condensor. Attach adapters to the existing LP and HP R12 fittings.

Vaccum system for 15 minutes. Remove vacuum and check after 15 minutes to ensure no leakge. If no leakage put in 20 - 24 oz of R134 refrigerant. The exact amount is 60 to 80 % of the full R12 charge.

I pull 48 deg at the vent on a 90 deg day, on the road.

Feel free to ask questions about any particular aspect.

Thank you shamaal! There was no freon at all in the system according to the people that were going to do the evacuation. After I change the compressor, drier, and orifice tube and get the flush done I have a friend that has a machine to refill it. I will be using the R134 especially after reading about the price of R12. Your information will help a lot more than you know. I could not find any mention about capacities on this anywhere. Thanks again.

The hose replacement issue has a couple different faces. 134a needs barrier hoses. Yet, it seems that the old hoses, when previously used with mineral oil *may* be ok. I do not take positions on this argument. I just note it. The 134a molecule is MUCH smaller than the R-12 molecule.