Sorry about the gap in response, life got busy.
Anywhoo...in a testament to being methodical and meticulous in what you're doing, the fix was provided to me at the beginning of this thread.
The problem was indeed the check valve going into the engine.
one of the first things that I did was to pull both check valves and manually apply suction to both ends. air passing one way and not the other with both...ok. I did't replace as I normally would do just to be sure as there weren't any aftermarket valves at local shops that were the right diameter.
after replacing/lubing etc etc all other connection points and not fixing the issues I told myself "I'd better verify those check valves again".
Sure enough, the dash valve was fine but with the engine check valve, after stopping air flow initially, I maintained suction on for a longer period and air started seeping through.
Replaced it from local Dodge dealer to the tune of 20 something bucks I think
and I just drove from the high Rockies to San Diego with perfectly working AC the whole way.
Thanks again for everyone's help! Unfortunately now I have to get it ready to sell and will probably be looking for pricing advice under the current circumstances :P
*fixed
Linear Mode
