| Message | best way to do that is to fkush the syetem of mineral oil, and refill with 7 ounces of ester oil and charge it up. You need to fix your leaks. R134a is cheap, so you could fix your leaks after filling with R134a, and then recharge with R12. It is still available. I bought some recently at O'reilley's, but you need the proper liscense 
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