Leak Tests
CHECKING FOR A/C LEAKS
WARNING: GOOD VENTILATION IS NECESSARY IN THE AREA WHERE A/C LEAK TESTING IS TO BE DONE. IF THE SURROUNDING AIR IS CONTAMINATED WITH REFRIGERANT GAS, THE LEAK DETECTOR WILL INDICATE THIS GAS ALL THE TIME. ODORS FROM OTHER CHEMICALS SUCH AS ANTIFREEZE, DIESEL FUEL, DISC BRAKE CLEANER OR OTHER CLEANING SOLVENTS WILL CAUSE THE SAME CONCERN. A FAN, EVEN IN A WELL VENTILATED AREA, IS VERY HELPFUL IN REMOVING SMALL TRACES OF AIR CONTAMINATION THAT MIGHT AFFECT THE LEAK DETECTOR.
1. Attach Rotunda R-134a Low-Side Quick Disconnect 176-R0036 and R-134a High-Side Quick Disconnect 176-R0037 or equivalent to the manifold gauge set.
2. Adjust both manifold gauge valves to the maximum clockwise (closed) position.
3. Adjust both quick disconnect valves to the maximum counterclockwise (closed) position.
4. Remove A/C charging valve cap from the A/C service port fittings and install quick disconnects.
5. Adjust both quick disconnect valves to the maximum clockwise (open) position.
6. Both gauges should show approximately 413-551 kPa (60-80psi) at 24°C (75°F) with engine off.
7. If very little or no pressure is indicated, connect a Refrigerant-R134a cylinder to the manifold gauge set and adjust the low-pressure manifold gauge valve to the counterclockwise (open) position. This opens the system to cylinder pressure.
8. Check all system connections, the A/C compressor center seal and shaft seal for leaks, using a Rotunda R-134a Automatic Calibration Halogen Leak Detector 161-R0010 or equivalent. Pass the leak detector along the underside of all points being checked. Refrigerant is heavier than air and will show most readily in those locations.
9. When performing leak tests of the A/C evaporator core with an electronic leak detector, test only at the evaporator drain tube and the evaporator core refrigerant line connections. Do not attempt to leak test at the instrument panel registers or inside the passenger compartment. Air flow from the blower and/or chemical odors inside the vehicle may cause false readings. This is especially important after the vehicle has been sitting in the sun and the vehicle's interior temperatures have risen above the ambient level.
LEAK DETECTOR, ELECTRONIC
Use Rotunda R-134a Automatic Calibration Halogen Leak Detector 023-R1003 or equivalent.
- The electronic leak detector is operated by moving the control switch to the ON position. The detector automatically calibrates itself when it is turned on.
- Move the probe at approximately 25 mm (1 inch) per second in the suspected area. When escaping refrigerant gas is located, the ticking/beeping signal will increase in sounds per second. If the gas is relatively concentrated, the signal will be increasingly shrill.
- Follow the instructions included with the detector to improve handling and operating techniques.
LEAK TRACER DYE
NOTE: The presence of oil at A/C spring lock couplings does not always indicate a refrigerant leak. Assembly plant processes apply oil to fittings prior to connection to aid in assembly.
When a fitting is suspected of a leak, always wipe the fitting clean and verify the leak with an electronic leak detector or R-134a fluorescent tracer dye. To achieve accurate results always follow the manufacturer's instructions included with the electronic leak detector or tracer dye.
R-134a fluorescent tracer dye has been added to the A/C systems of new vehicles. Leak checking can be performed with an ultraviolet lamp and is an acceptable alternative to using an electronic leak detector.
The fluorescent lifespan of the leak tracer dye is 500 hours of A/C system use, after which another injection of dye is required. A/C system pressure must be above 550 kPa (80 psi) for this operation.
Scan all components, fittings and lines of the A/C system with Rotunda Ultraviolet Lamp 164-R0721 or equivalent. The exact location of the leak or leaks can be pinpointed by the bright yellow-green glow of the tracer dye. Since more than one leak may exist in the system, always inspect each component.
The best leak detection results will be achieved in conditions of low ambient light. In the areas that cannot be reached by the UV lamp, use a mechanic's mirror or use a non-fluorescent shop towel and wipe the suspected area and then check the towel with the UV lamp for traces of the dye.
After the leak is repaired, the the traces of dye can be removed from the previously leaking area by using any general purpose oil solvent.
Verify the repair by operating the A/C system for a short while and reinspecting the system with the UV lamp.
Rotunda R-134a Fluorescent Tracer Dye 164-3712 or equivalent may be introduced into the A/C system using Rotunda R-134a Fluorescent Tracer Dye Injector 164-3711 or equivalent. Inject the dye and check for leaks as follows:
1. Close valve on dye injector.
2. Connect the hose end of the dye injector to the system low pressure gauge port valve. Tighten securely.
3. Close both valves on gauge manifold set and connect the center hose to a charging cylinder. Leave center hose loose at gauge manifold. Momentarily open charging cylinder valve to purge air out of the center hose, then tighten the center hose at the gauge manifold connection. Close the valve on the charging cylinder.
4. Connect gauge manifold low pressure hose to dye injector, leaving the connection at the gauge manifold loose.
5. Open dye injector valve to allow A/C system pressure to purge air from the dye injector reservoir and the low pressure hose to the gauge manifold. Tighten the hose connection at the gauge manifold. Close valve on dye injector.
6. Remove reservoir cap from top of the dye injector reservoir and fill reservoir with 7 ml (0.25 ounces) of Rotunda R-134a Fluorescent Tracer Dye 164-3712 or equivalent.
7. Replace reservoir cap. Tighten securely.
8. Open valve on charging cylinder, then open manifold gauge low pressure valve. Open valve on dye injector for 5 to 10 seconds to allow the dye to be forced into the A/C system. Close dye injector valve. Close manifold gauge low pressure valve and valve on charging cylinder.
9. Start engine and operate the A/C system at MAX to stabilize the system (approximately 10-15 minutes).
10. Shut engine OFF.
11. Disconnect all hoses slowly to dissipate any residual refrigerant pressure that may be present.
12. Using Rotunda Ultraviolet Lamp 164-R0721 or equivalent, check system for leaks. The tracer dye will glow a bright yellow/green when the ultraviolet light hits it.