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Convertering R134a compressor back to mineral oil, how?

Leggie on Fri July 13, 2012 5:36 PM User is offline

My system is still original R12. A compressor I'm buying off of a wrecked car has already been used with R134a and POE or PAG oil.

How do completely clean out the R134a oil so I can use it with MO and R12 in my car?

bohica2xo on Fri July 13, 2012 7:31 PM User is offline

You flush the compressor with the oil you intend to use.

Compressor Flushing Procedure


"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Cussboy on Fri July 13, 2012 8:57 PM User is offline

In 2003 the Air Pro rebuilt compressor for my '88 that I bought from the board sponsor was filled with oil for R134a (I checked it by FTIR spectroscopy). I flushed it with R-12 type mineral oil a few times, then filled it and used it. Still good.

Co-worker a month later bought Air Pro rebuilt compressor there for his '90 (both Mazdas), that had correct mineral type oil in it already.

mk378 on Fri July 13, 2012 10:24 PM User is offline

Check your used compressor for leaks first. After completely assembling it, check any R-12 system for leaks under pressure with some other gas before committing to charge with R-12.

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