I checked my low side pressure, and it was too low. So I added 12 oz of es-12. The reading was 50 lbs when it should have been 70 lbs, so I ordered another can and will install it when it comes. I have ac, and always have had some, although here a little ac goes a long way.

My question is "how much oil to add?" I have a 3 oz can available. I finally figured out from reading all these ac threads that the constant smear on the drivers side of my engine is from the ac system, and not the ps reservoir.

The system holds some pressure so there is not knowing how long it's been since any oil was added. Should I add any?