i have seen a guy imran in model town, he installed the new AC in a mehran (replaced the factory fitted) car was i think 2004 or 05 made... overheatign was the issue... he replaced something donno what was in the replacement list...
but the AC was (Y) zabardast... and the car was standing still with AC on for hours
heat guage was somewhere in the lower middle half...
if u need contact number of that guy let me know and i'll arrange it for u
btw yes AC works fine with CNG in mehran