How cold should the air be when coming out of the vents?

Answer 1

IAW pressure/temperature charts.....R134a (with a new or reasonably well conditioned compressor), will give you a gauge reading in pounds that equates to a specific temperature within the evaporator. theoretically you could have air at the equivilent low temperature that your gauges are reading ......however, warm air in your car flowing through the evaporator will effect the cold temperature within the evaporator because that is how air conditioning works...(the colder temperatures within the evaporator adsorbs the heat of the air passing through it) ect., .....thus, on a general basis you can add 11-15 extra degrees to the correlated temperature that your low side gauge reads and that would be the air temperature coming out your vents into the car.......for example: let say your low side gauge (after running for a few moments) equates to a temperature of 35 degrees f. then you could expect a temperature coming out of the vents to be around 46 - 50 degrees f. ..... so on and so forth.......bear in mind that a hot car with temperatures in the 100's of degrees will not register these kinds of temperatures until and unless you recirculate your inside air. It is only after you have reduced the temperatures within the vehicle to a reasonable level that you would find the above equation to have any merits. I hope this has been helpful and answered some of your questions....I am a State Licensed Heating and Air Conditiong Contractor.