I am going to flush my air conditioning system in my 84 300SD. The R-4 compressor is running just fine, but there is too oil much in the system. The car had R-12 (mineral oil), then was converted to R-134a (do not know what kind of oil). There was way too much oil in the system because the oil bubbled out of the service port when I removed the gauge. So I flushed the system and put mineral oil and Duracool in it. I think I put too much oil in the compressor.

I used a flush agent with my blow gun to flush the system, but I thought the agent was too thick. It was possible some was left in the system.

I was told you could use paint thinner or mineral spirits, but it would leave a residue.

I think dechrolinated brake parts cleaner is good because it cleans well and dries fast.

So, which is the best solution to flush an air conditioning system?