AC Question

[dadsmax]

I converted a 1987 Ram 50 AC to 123a. How much refrigerant and pag oil does the system take? It’s a Mitsubishi system.

[dadsmax]

134a, sorry for the typo.

[dadsmax]

I have looked in the Hayes repair manual and all over the internet. I only found one reference and it said to see the decal under the hood. I don’t have the original hood.

[FMS88]

The 88 factory service manual specifies 32 oz. of R-12 refrigerant and 2.7 oz. of compressor oil. Don't know if these amounts differ for other years or types of refrigerant.

Here's a PDF of the 1988 A/C Service manual:

28475

[85Ram50]

The 88 factory service manual specifies 32 oz. of R-12 refrigerant and 2.7 oz. of compressor oil.
28475

Now that you have this there are a lot of "R12-R134a refrigerant conversion charts" online with one search of the quoted< line I didn't find anything clear about the amount of oil.

[pennyman1]

DO NOT USE PAG OIL!!! Pag oil reacts with the R-12 refrigerant oil, and will destroy the system. Only use ester oil in converted systems. No amount of system flushing with remove all of the r-12 mineral oil. For best results you should also replace the expansion valve for one calibrated for R-134A. Start with about 90% of the R-12 charge then add from there to prevent over pressuring the system. Oil charge should be the same amount as r-12.