How to find AC leak in your car and get the cold back again

Learn the most effective ways to find AC leak in your car

AC systems can develop leaks over time, compromising their efficiency and potentially leading to complete failure. This article will explore the causes, symptoms, and solutions for AC leaks in cars, helping you maintain a cool and comfortable driving environment. It all starts by finding the AC leak and fixing it. Here are the two best ways to find an AC leak in a car.

Find an AC leak using an electronic AC leak detector

Some auto parts stores rent electronic AC leak detectors. The good ones are very effective at finding even the smallest leaks. To use an electronic detector to find AC leak, start by charging the system.

Electronic AC leak detector

With the engine running and AC set to MAX, slowly pass the detector sensor around the most common leak sites, like joint fittings at the compressor, condenser and receiver dryer. Next, pass the sensor across the entire surface of the condenser.

The electronic leak detector will light up and beep to indicate a leak. The advantage of an electronic leak detector is that you can start testing as soon as you fill the system.

If you don’t have access to a high-quality electronic sensor, you’ll have to use dye and a black light.

How to use dye to find an AC leak

Purchase a DIY dye kit and add the dye to your AC system before you charge it with refrigerant.  inject it into the system in one of two ways: when it is empty or by using an injector tool.

Your best bet may be to buy or rent an entire kit. The kit contains everything you need to inject dye and find the leak.

The kit contains everything you need to inject dye and find the leak.

with the dye, injector, black light, and goggles. The injector tool screws onto a charging port and forces the dye into the system when it already has a refrigerant charge. After injecting the dye, operate the vehicle for several days to allow the dye to escape near the leak. Then, a black light is used to spot the glow emitted from the dye.

I’ve used both methods to find AC leak. An electronic A/C leak detector can be fooled if you’ve used any spray cleaners recently. However, A/C leak detection dyes are pretty foolproof. If your black light spots a leak, it’s not lying.

The most common AC leak points

• Leaking seals where the hoses connect to the compressor
• Leaking seals at the expansion valve
• Leaking seals at the condenser
• Leaking valve cores at the high and low side ports. See this post on how to replace leaking valve cores without having to evacuate the system.
• Hose joints with O-rings
• On hoses, leaks usually occur near the crimp connector

This image shows leaking refrigerant at the hose crimp connector

Another example of a leak at the Crimp Connector

Notice the leak at the upper connection

This image shows a refrigerant leak at the O ring connecting the low pressure line to the compressor

©, 2015 Rick Muscoplat