How to Check for a Freon Leak

A leaking air conditioner leads to frequent recharges.

The air-conditioning system of your vehicle is a sealed system under high pressure. Over time, damage may occur to the system and create a leak. Not only is this leak harmful to the environment, but it can also be costly to you. The most reliable way to locate a refrigerant leak in a car's air-conditioning system is to use a U.V.-dye system. This will make the leaking area glow under a black light, allowing for a simple diagnosis.

Things You'll Need

• Repair manual (Chilton's or Haynes)
• U.V.-tinted R134a refrigerant kit
• U.V. glasses
• Black light

Instructions

1. Open your vehicle's hood and locate the low-pressure air-conditioning line. This line is the thicker of the two air-conditioning lines and can be precisely located using the repair manual.

2. Trace the low-pressure line until you reach the metal service port, a small metal valve, on the line. Remove the service port's cap by twisting it counterclockwise.

3. Connect the U.V.-tinted R134a kit's fill hose to the service port by pulling up on the plastic ring on the end of the hose, pressing the hose onto the port and releasing the plastic ring. Turn your vehicle's engine on and run the air-conditioning system on "High." Fill the air-conditioning system using the instructions included with the R134a kit --- it's typically as easy as pulling a trigger.

4. Allow the vehicle and air conditioner to run for five to 10 minutes and turn the vehicle's engine off.

5. Put the U.V. glasses on and search the entire engine compartment for traces of U.V. dye using the black light. The U.V. dye puts off a greenish tint when the black light hits it. Any large amounts of U.V. dye or the tinted R134a spraying from the line indicates a leak.