How To Use AC Pro

AC Pro

Is your air conditioner blowing warm air?

An air conditioner that's blowing warm air is frustrating, both because it's uncomfortable sitting inside a vehicle on a hot day while stuck in traffic and because AC system problems have a reputation as being expensive to fix. But before you jump to conclusions, stay cool. Your AC problem may simply be the result of a low refrigerant level.

If that is the case, there's a quick, easy, and inexpensive DIY solution. Add some refrigerant using a can of A/C Pro, and you may be able to nix the problem in under 15 minutes. In addition to replacing lost refrigerant, A/C Pro seals minor AC system leaks that may have caused the problem in the first place.

Beginning with the 1995 model year, all vehicle AC systems were required to use R-134 refrigerant, replacing R-12 refrigerant (also known as Freon) because it was harmful to the earth's ozone layer. If your vehicle is a 1992-, 1993-, or 1994-year model, it could contain either type of refrigerant, so you should first consult with your mechanic before attempting to recharge the system.

Follow these steps to recharge and restore your vehicle AC's cooling breezes.

Vehicle System
Skill Level

This is a good project for new DIYers

Time to Complete
About an hour
  1. Start the vehicle and turn the AC on to the coldest setting with the fan speed at its highest.

  2. If there's no question that hot air is coming out of the vents, proceed to step 3. If the air feels like it might be cool but not as cool as it should be, invest in a thermometer to test the AC temperature. Simply stick it in one of the vents, wait a minute, and then read the temperature. It should register around 40-45 degrees on a typical 70- to 80-degree day.

  3. Look under the hood and locate the AC compressor to determine if it's running or not. If the engine is running, the pulley attached to the compressor will always be moving, turned by a belt. To determine if the compressor is running, look at the pulley's center for a clutch that should also be spinning when the compressor is running. If this clutch isn't moving, the compressor isn't engaged. Some AC compressors won't run if the refrigerant level is too low, so don't assume the compressor is the problem.

  4. AC systems have two different-sized ports—a "high" side and "low" side. To locate the vehicle's low-pressure or low-side AC port, look under the hood for the larger diameter aluminum tube that's coming from the compressor. There should be a colored, plastic cap attached and perpendicular to that aluminum tube. This is the port that you want to connect to. A/C Pro will only fit on the low side port, so there's no need to worry about connecting to the wrong port.

    AC system low-pressure port

    The low-pressure port cap is marked with an L for easy identification | Lisa Kowite

  5. Remove this plastic cap from the port. If you have trouble locating the port, consult your owner's manual or visit A/C Pro's online port locator.

  6. Remove any protective packaging and the shipping disk from the neck of the A/C Pro can.

  7. Attach the can's hose to the low-pressure port. Do not squeeze the trigger yet.

  8. Look at the can's gauge. Turn the dial to so that the arrow aligns with the outside temperature.

  9. Still looking at the gauge and with the AC compressor running, determine where the gauge needle lands in relation to the “V" on the gauge's face. If the needle is below or to the left of the V, you'll need to add A/C Pro. If the needle is between the V, the system is fully charged and doesn't need refrigerant added. If the needle is to the right of the V in the red zone it usually indicates that the compressor isn't running. Confirm that the compressor isn't running, and then try adding a little A/C Pro to see if the compressor turns on. If it doesn't you'll need to consult a mechanic for advice.

  10. To add A/C Pro, squeeze the trigger, rotating the can up and down and gently shaking it as you do. Continue squeezing the trigger until the gauge's needle falls within the V, indicating that the system is fully charged. Don't overcharge the system by adding too much refrigerant and causing the needle to land outside the V.

  11. Remove the can's hose from the low-pressure port and replace the cap on the port. If there's still R-134 refrigerant left in the can, save it for the next time the system needs a recharge.

Last updated May 12, 2020