Astro, Safari 1997-2005

Testing The System


Leak Testing

The following tools may be required

J 39400-A Halogen Leak Detector
J 41447 R-134a A/C Tracer Dye-Box of 24
J 42220 Universal 12 V Leak Detection Lamp
J 43872 Fluorescent Dye Cleaner
J 46297 A/C Dye Injector Kit
J 46297-12 Replacement Dye Cartridges

Fluorescent Dye Leak Detection

Fluorescent dye will assist in locating any leaks in the A/C system.

PAG oil is water soluble. Condensation on the evaporator core or the refrigerant lines may wash the PAG oil and fluorescent dye away from the actual leak. Condensation may also carry dye through the HVAC module drain.

Leaks in the A/C system will be indicated in a light green or yellow color when using the leak detection lamp. Use the leak detection lamp in the following areas:

All fittings or connections that use seal washers or O-rings
All of the A/C components
The A/C compressor shaft seal
The A/C hoses and pressure switches
The HVAC module drain tube, if the evaporator core is suspected of leaking
The service port sealing caps The sealing cap is the primary seal for the service ports.

Follow the instructions supplied with the J 42220.

To prevent false diagnosis in the future, thoroughly clean the residual dye from any area where leaks were found. Use a rag and the approved fluorescent dye cleaner J 43872.

Only use dyes approved for use with General Motors vehicles. Not all of the fluorescent dyes are compatible with PAG oil. Some types of dye decrease the oil viscosity or may chemically react with the oil. To put the dye into the A/C circuit:

J-41447 can be poured directly into a removed A/C component
J-46297-12 is injected into the low side port using J-46297

R-134a leak detection dye requires time to work. Depending upon the leak rate, a leak may not become visible for between 15 minutes and 7 days.

DO NOT overcharge the A/C system with dye. Use only one 0.25 oz (7.39 ml) charge.

To prevent false diagnosis, thoroughly clean any residual dye from the service port with a rag and the approved fluorescent dye cleaner J 43872.

Halogen Leak Detector

Caution: Do not operate the detector in a combustible atmosphere since its sensor operates at high temperatures or personal injury and/or damage to the equipment may result.

Ensure that the vehicle has at least 1 lb. (0.45 kg) of refrigerant in the A/C refrigeration system in order to perform a leak test. Refer to Refrigerant Recovery and Recharging the A/C system procedure in this section.

Halogen leak detectors are sensitive to the following:

Windshield washing solutions
Many solvents and cleaners
Some adhesives used in the vehicle

Clean and dry all surfaces in order to prevent a false warning. Liquids will damage the detector.

Follow a continuous path in order to ensure that you will not miss any possible leaks. Test all areas of the system for leaks.

Follow the instructions supplied with the J-39400-A.

Refrigerant Leak Testing

General Motors vehicles are now manufactured with fluorescent dye installed directly into the A/C system.

The fluorescent dye mixes and flows with the PAG oil throughout the refrigerant system.

Verifying some passive leaks may require using the J-39400-A, even though the A/C system contains fluorescent dye.

The only time that adding additional fluorescent dye is required is after flushing the A/C system.