Lessons on leak detection

Cappert discusses questions about leak detection products

In this issue's column, we cover your questions related to leak detection in various systems. State-of-the-art technologies continue to breed new solutions and approaches to chasing down pesky leaks. Let's see what piqued the curiosity of PTEN readers.

Q. I was at an air conditioning class this summer and heard the EPA approved a new refrigerant for auto A/C systems. Will our shop need yet another leak detector to trace leaks in these new systems?

A. THE USEPA formally listed HFO-1234yf refrigerant as an acceptable refrigerant back in March 2011. At this writing, the feds have not yet passed any regulations stating what's required to work on HFO-1234yf systems, which would impact A/C refrigerant handling equipment, refrigerant identifiers and leak detectors. However, the Society of Automotive Engineers (SAE) has published numerous new standards for working with HFO-1234yf refrigerant, in collaboration with the automotive industry. As part of this "suite" of new standards, SAE J2913 spells out the minimum performance criteria for electronic leak detectors to be used with HFO-1234yf. Electronic leak detectors meeting the performance criteria in the new SAE standard will have a label affixed, "Design certified by (name of testing laboratory) to meet SAE J2913 (with lettering in bold face)." If history is any indication, EPA will likely adopt the new SAE standards as the framework for regulations surrounding service on the new A/C systems. Since GM plans to use HFO-1234yf, in its 2013 models, you can bet on hearing something soon from EPA on new regulations.

Q. We'd like to use a dye-based detection system, but have concerns about the dye's effects on coolant color and integrity. Since we work on practically all makes and models, does this rule out using this kind of technology?

A. No, some manufacturers of dye-based systems are well aware of the potential issues caused by dyes when used for this purpose. Accordingly, they've concocted special dye formulations that do not affect coolant color nor integrity. When using dyes, always follow the manufacturer's recommended ratios to ensure you're using the proper amount of dye for the system being tested.

Q. We use dye detectors, but find that getting into cramped areas can be difficult with the ultraviolet lamp. Are there any tricks we can use to get around this limitation?

A. While you certainly can use a mirror to reflect the light into those tight spaces, you won't always have the room to use a mirror, either. For tight quarters, use one of the portable, flashlight-type detection lights. Using LED technology, they give you the utility of not only being able to detect dye at the source of a leak, but the light also doubles as a flashlight for other purposes.

Q. When choosing a dye for air conditioning leaks, are there any special considerations I should take into account?

A. Yes, make sure the dye you choose does not contain any solvents that may have a negative effect on the system. Solvents can impair the viscosity and lubricity of refrigerant oils, which could potentially cause damage to the compressor and other system parts. Always check with the manufacturer to make sure the dye is free of solvents.

Q. We get our share of cars with vacuum leaks, and we've had some comebacks due to missing a leak during a visual inspection. Is there a more positive way to find vacuum leaks?

A. One emerging technology that fits the bill perfectly for these types of leaks is called a smoke machine. When sleuthing out a vacuum leak, you feed artificial smoke from the smoke machine into the intake manifold, and then thoroughly inspect all potential leak points for escaping smoke. The smoke machine also works well when tracking down leaks in EVAP systems and HVAC controls. Some machines provide ultraviolet-light enhanced smoke to make leaks even more evident. This allows further discrimination of leaks, through use of a detection light.

Q. Our tool rep has a deal on electronic vacuum leak detectors. How do they work and are they effective?

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