Refrigerant Leak Testing

Refrigerant Leak Testing

Tools Required
J 39400-A Halogen Leak Detector
J 41447 R-134A A/C Tracer Dye-Box of 24
J 41459 R-134A A/C Tracer Dye Injector
J 42220 Universal 12 V Leak Detection Lamp
J 43872 Fluorescent Dye Cleaner

IMPORTANT: This Isuzu vehicle is now manufactured with fluorescent dye installed in the A/C system.

The preferred method of leak testing is the use of fluorescent dye. J 41447 is the only dye approved. Follow the Fluorescent Dye Injection procedure for vehicles that do not already contain the fluorescent dye.

Fluorescent Leak Detector
- Fluorescent dye will assist in locating any leaks in the A/C system.
- The J 41447 dye mixes and flows with the PAG oil throughout the refrigerant system.

IMPORTANT: 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.
- 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.

Fluorescent Dye Injection

IMPORTANT: J 41447 is the only approved A/C leak detection.

- Not all of the R-134a dyes are compatible with PAG oil. Some dyes decrease the oil viscosity or may chemically react with the oil.
- 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.

IMPORTANT: Do NOT overcharge the A/C system with dye. This may cause reliability problems. Use only one 7.39 ml (0.25 oz) charge bottle of J 41447.

- With the A/C system charged, add J 41447 to the A/C system using J 41459. Follow the instructions provided with J 41459.
- To prevent any false diagnosis, thoroughly clean any residual dye from the service port with a rag and the approved fluorescent dye cleaner J 43872.
- The dye injection package contains a notice sticker. Complete the leak detection information and place the sticker near the charge label.

A/C Compressor Shaft Seal Leak Detection with Dye
Use J 43872 to clean all traces of fluorescent dye from the A/C compressor shaft seal and reinspect the compressor.
1. Run the A/C system 15-30 minutes depending on the type of leak in order to circulate the dye.
2. Use J 42220 to inspect the A/C compressor shaft seal.
3. To prevent false diagnosis in the future, thoroughly clean any residual dye from the area of the leak with a rag and the approved fluorescent dye cleaner J 43872.

Service Ports
The sealing cap is the primary seal for the service ports. The cap contains an O-ring gasket that provides a leak-free seal. Install the cap tightly for leak-free sealing. The following conditions will cause a refrigerant loss:
- A loose cap
- A missing cap
- An incorrect cap

Use J 42220 or J 39400-A in order to test the service ports and sealing caps for leaks.

To prevent a false diagnosis, thoroughly clean any residual dye from the service port or sealing cap with a rag and the approved fluorescent dye cleaner J43872.

Evaporator Core
Use J 42220 in order to inspect the HVAC drain port. Follow the Fluorescent Dye Injection procedure if the A/C system does not contain fluorescent dye. If only J 39400-A is available complete the following steps:
1. With the engine running, turn the A/C ON.
2. Select the maximum blower motor speed for at least 15 seconds.
3. Turn OFF the engine.
4. Turn OFF the blower motor.
5. Wait 10 minutes.
6. Turn ON the blower motor and select the lowest speed.
7. Insert the leak detector probe into one of the center instrument panel outlets. Try to get as close to the evaporator as possible.
8. A solid alarm on the detector indicates a leak.