can hear my compressor coming on, but there's no cold air. What's wrong?
A: There could be several
reasons why your auto A/C compressor is coming on (or cycling on and off)
but you still do not have cool air coming from the vents in the car. In
general, the reason is that the A/C system is under a
condition. That means there is not enough liquid refrigerant in the A/C
evaporator to effectively transfer the heat.
The superheat condition is caused
by only one of two reasons. Either there is a problem with the refrigerant
flow and that is restricting the amount of refrigerant entering into the
evaporator OR the system is low on refrigerant and there simply is not enough
refrigerant to maintain the proper liquid level in the evaporator.
The quickest method to test this
is to add a small amount of refrigerant (usually between 2-4oz. depending
on the total system charge). If the added refrigerant corrects the problem,
you most likely have a leak and the system should be recovered, have the
leak repaired, vacuum and recharge the A/C system with the original factory
specified amount of refrigerant. If the added refrigerant did NOT improve
the cooling, you most likely have a restriction within the A/C circuit. That
could be at the condenser, drier or expansion valve or orifice tube. The
system will have to be
order to determine the real problem.