【How-to】What is the difference between r12 and r12a

R134a systems operate at higher discharge-side pressures than R12, which can cause compressor seals to leak. Bottom line, R134a simply doesn’t cool as well as R12. … R12 systems used mineral oil, but unfortunately mineral oil doesn’t dissolve in R134a. So, along with R134a came a new oil: Polyalkylene Glycol—or PAG oil.