Afganistan has been referred to as "the roof of the world." Keeping this in mind, altitude may be your problem.
Over about 4000 ft, you need to take the thinner air into account in two ways. First, motors will not be cooled as efficiently; this is compounded if there is little humidity.
Secondly, a different table is used in charging the system with refrigerant- with the result of there being 'too much' used, and everything suffering.
