Springtime means A/C system maintenance

We have had a wonderful start to spring. Our family so enjoys the warm, bright sunny days. However, this is also the season when you begin to use your car’s air conditioning again. Some will discover that their car is no longer making cold air this spring.

You might be surprised to learn that in most cars and trucks the heater is operating 100% of the time. When you select the air conditioning mode on the dash, the air conditioner begins to produce cold air in a separate coil beside the heater coil. The air conditioner coil will produce 40 degree air. A damper then blends the very cold air with the very hot air to produce the vent temperature that you select with your temperature knob.

Sometimes the damper that blends the hot and cold air malfunctions. The problem could be the actuator that moves the damper, the damper itself can break, or it could be both. The damper is a plastic door, with plastic tabs for hinges, in a plastic case. After several years of use the plastic will sometimes break.

If your car will produce luke warm air when selecting either very cold or very hot, then you may have problems with the blending damper or actuator.

If you can get very hot air, but you cannot get very cold air, then you probably have problems with the air conditioning system. The most common cause of this problem is a leak. The air conditioning system uses a gas to produce cold. The gas is commonly called Freon, although the current gas is actually called R134a.

Most cars use 2 pounds of Freon, while most vans and SUV’s use 3 to 4 pounds of Freon. The air conditioner will work without a noticeable difference when it is 1/2 pound low. When the system looses 1 pound or more the air conditioner will no longer produce cold air.

A leak test begins by recovering all of the Freon from the A/C system. The amount recovered is compared to the specified amount for the vehicle. The system is then charged with a full charge of Freon. You should only have to pay for the additional Freon, not the full charge. The A/C system is then operated. An electronic Freon detector is used to detect the location of the leak. The Freon detector sounds like a Geiger counter. It slowly beeps until it comes into the presence of Freon, at which point it goes crazy. A certified A/C technician moves the detector throughout the system to determine any of the points where it may be leaking.

Your A/C system might develop a new leak after an A/C repair. A full and properly operating A/C system produces pressures as high as 400 pounds. A system low on Freon runs at a lower pressure. Prior to the repair the A/C system was running at reduced pressure. Once the system is restored to normal pressure, another weak point may develop a new leak. No leak detection system can predict where a future leak will occur. If your system develops a new leak, it does not mean that someone failed to identify the leak correctly in the first place. It is most likely that a new leak occurred after the system returned to normal operating pressure.

Brian Klaubert owns Christian Brothers Automotive – Hamilton Mill, on Braselton Hwy in Dacula. They are “Best of Gwinnett” winners in both the Gwinnett Daily Post and Gwinnett Magazine.