Tech tips A/C problems Have recently overhauled your A/C and it is still not blowing cold? Ok, there seems to be a myth with the A/C systems that you need to get a new dryer and to vacuum the system to get the system to blow cold. We have recently replaced the condenser on our own Town Car without buying a new dryer or vacuuming out the system. We had a hole in the condenser over 2 years and simply replaced the bad component and added freon. Blows cold as before. NOW: There are things that can cause the system not to blow cold. The older systems used an "icing" switch which opened or closed the expansion valve allowing flow of freon into the evaporator core. One sure sign there is something wrong is if you see frost building on the pipe directly behind the expansion valve. There may be a clog in the evaporator. This normally happens if you had a compressor lock up and didn't change the evaporator or dryer. The small metal particles travel through the system and lodge themselves in small spaces. Have an A/C tech check pressure in the system. Extreme high pressure may mean a clog. Not necessarily too much freon.