Yep, AC flush with solvent and compressed air. Did the evaporator and condenser individually. New manifold and lines(they are a single assembly for the A6) from the compressor to the condenser and from filter/dryer to compressor. New orifice tube(blue) and all new o-rings everywhere. New R134 pressure switch from oreilly(it was ~$20). Flushed the compressor also and then used PAG 150 in the compressor reservoir(this was my mistake, I should have torn it down and cleaned/rebuilt it then). I vacuumed it for about 2 hours and then made sure it held vacuum overnight to check for leaks. Then charged it with about 36oz of R134. It worked great for about a year and then blew the compressor shaft seal(common problem on the A6 with the old ceramic shaft seal). It didn't blow until I was on a hunting trip in September, so I never got around to fixing it until the temps warmed up again a few weeks ago. I got a compressor rebuild kit from ebay with the new design double lip shaft seal and tore the whole thing down and rebuilt it. It took about 4 hours, mostly going back and forth trying to get the clutch off the front. Then re-vacuumed and charged the system and it's back to tip-top cooling.
Did you use the original type tube and fin condenser or a parallel type condenser?
I changed mine over to the parallel condenser type last year, because I couldn’t find an original type tube and fin. I also put 36 oz of 134 refrigerant. It was nice and cold but I noticed my high pressure side was pushing 300-320psi with low side in the 70-85 psi range. A couple days later, I’m guessing when the outside temperature was higher, it popped the compressor high pressure relief valve.
I emptied the system and started over with a 1 hour vacuum then started refilling 134A while watching pressures. At 170-180psi high side and 35-40psi low side, I had 27 oz of 134A in the system. My dash vent outlet was at 37 degrees.
I went with 36 oz of refrigerant based on information on this forum last year.
I don’t think it took into account the parallel flow condenser vs the tube and fin type. The parallel flow condenser (16”x28”x1”) is smaller in dimensions than the original round tube and fin type. Also the round tube I.D. volume is higher than the small rectangular type tubes in the parallel flow type condenser.
Either way, with this month’s temperature running 101-103 in my area, the A/C was still blowing cold “until I got caught in traffic idling for 20-30 minutes at a time”. My engine temperature also came up significantly, from 180 to 235. And as expected my AC temperature went up.
I’m in the process of installing an auxiliary 14” Derale electric fan in front of the condenser. I’ll post results when I get it back together, hopefully by this weekend.