Hmm, at 90F, I'd expect lower temps than 45, but there are a LOT of variables. more refrigerant raises the temps... but the vent temp can be lower if volume is low, and you increase it. the rub comes when you raise the pressures, and it goes beyond the evaporation point, and liquid exits the evaporator, then the bearings get washed of oil... damaging things...

are your evap and condenser coils clean?

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!