Test for leaks whenever you suspect a refrigerant leak in the system. You should
also test for leaks whenever you perform a service operation, which results in disturbing
the lines or the connections. Leaks are commonly found at the refrigerant fittings
or at the connections. Leaks are commonly caused by the following conditions:
| • | Dirt or lint on the O-ring seals |
Liquid Leak Detectors
Use a liquid leak detector solution on locations such as fittings. Apply the
solution to the area in question with the swab that is supplied with the solution.
Look for bubbles to appear. This will indicate the existence and location of any leak.
For areas that are not practical, such as sections of the evaporator and the
condenser, an electrical leak detector is more useful.
Electronic Leak Detectors
Follow the manufacturer's instructions for calibration, operation, and maintenance
of an electronic leak detector.
Battery condition is especially important to the accuracy of a portable model.
Set the detector to R-134a before beginning the test.
Important: Electronic leak detectors are sensitive to
windshield washing solutions, solvents and cleaners, and certain vehicle adhesives.
Surfaces must be clean to prevent false readings. Make sure that all surfaces
are dry to prevent damage to the detector.
General Testing Instructions
| • | Follow the entire path of the refrigerant system. |
| • | Completely circle each joint at 25-55 mm (1-2 in)
per second. |
| • | Hold the probe tip within 6 mm (0.25 in) of the surface. |
| • | Do not block the air intake. |
The audible tone changes from 1-2 clicks per second into a solid
alarm if there is a leak. Adjust the balance control to maintain 1-2 clicks
per second.
Test all of the following areas, even after one leak has been confirmed:
| • | Evaporator inlet and outlet |
| • | Receiver-drier inlet and outlet |
| • | Condenser inlet and outlet |
| • | Brazed and welded areas |
| • | All fittings and joints |
Testing Refrigerant Charge Ports/Access Valves
The sealing caps provide protection for the refrigerant charge ports. Make sure
that these caps are not missing or loose. Always use the correct cap for each port.
Testing the Evaporator Core
Leaks in the evaporator core are difficult to find. Test the evaporator core
using the following procedure:
- Run the blower fan at speed setting 4 for at least 15 minutes.
- Turn the blower to OFF.
- Wait for 10 minutes.
- Remove the blower motor resistor. Refer to
Blower Motor Resistor Replacement
.
- Insert the leak detector probe as close as possible to the evaporator
core. The detector will indicate a leak with a solid alarm.
- Use a flashlight to search for refrigerant oil in the core surface.
Testing the Compressor Shaft Seal
- Blow shop air behind and in front of the compressor clutch/pulley for
at least 15 seconds.
- Wait 1-2 minutes.
- Probe the area in front of the pulley. If the detector emits a solid alarm,
there is a leak.
