[DieselSJ]

Vent temp depends on the ambient air temp. System should be tested with engine at 1500rpm, A/C on full, with doors/windows open. If you are getting 52 degrees and it is 102 ambient, a 50 degree drop is excellent. Sure, I can get the vent temp in my 87 down into the 30's, but that is after the cab is cooled down into the 80's. You want to judge based on drop from ambient, not the actual vent temp itself.