Low refrigerant levels cause an air conditioning system to lose its ability to blow cold air. Leaks in an A/C system commonly cause the system to lose refrigerant. The difficulty in finding an A/C system's leaks depends on the size of the leak. Small and hidden leaks require the use of a dyed refrigerant that increases their visibility. Car manufacturers install dye in a vehicle's A/C system in the factory. Time and dilution by added refrigerant cause the dye to be ineffective in leak detection.
Open the vehicle hood. Slide the end of the vehicle's hood prop in the provided notch to keep the hood from falling.
Follow the aluminum tubing running from the front of the engine until you locate a plastic cap. Remove the plastic cap from the refrigerant low-side refill valve.
Thread the end of a dye refrigerant can on the fill valve threads. Depress the button on top of the can to release dyed fluid into the A/C system. Release the button when the needle of the pressure gauge -- attached to the can -- points in the green. Remove the end of the can from the A/C fill valve. Replace the threaded cap on the fill valve.
Start the vehicle. Turn the A/C to "Max" and the fan speed to "High." Allow the vehicle to run.
Hold a lit UV light in the vehicle engine compartment. Mark any areas where the dye fluoresces under the light.
Turn off the vehicle. Close the vehicle hood.
