A/C systems in vehicles have improved significantly over the years, getting much tighter and less prone to leaks. A small leak in a vehicle system may take months or years for an owner or technician to notice, and in turn, may take a lot longer to find when the system fails. There are several ways to determine if a system has a leak, and then to locate the leak.
Taking a vacuum gauge to a vehicle system is a great way to determine whether or not a system is leaking, but won’t help you locate the leak. It’s usually the first step in confirming a leak, showing whether or not the system allows you to pull a sufficient vacuum. Set up your gauge in line with the system, let it run a few minutes and compare vacuum pressure with the system specs. Uneven or spikes in pressure means you have a leak.
Using UV dye may be the best way to pinpoint a leak in a system, but can also be time-consuming. Once injected into the system, the dye must circulate, which can take a day or a week depending on the system and its use. It also may require certain conditions be met before it starts to leak – RPM, throttle opening, elevation, overall speed, etc. Any small variance can impact the system, and therefore, the leak. It’s the most accurate in pinpointing the exact leak location, but can require patience, and asking the customer to return at a later date.
An electronic leak detector may give you a more immediate answer as to the location of a leak, but requires more immediate hands-on work. You’ll need to run a probe across all lines and joints on the system, or where you think a leak may exist, which can take some time. It’s also not 100% accurate, and may result in a false positive, so be careful and take your time.
The aftermarket industry has advanced its engineering in line with the OEs, trying to find the smaller, pin-sized leaks that may occur in today’s modern, tighter systems. Detecting leaks can be tough, but the first step is to check OE specs and the vacuum pressure on the system, then start tracing down the system to find the culprit. Once you find the leak, patch it and test the system again with a vacuum gauge. What do you find as the best way to locate leaks?