System Leak Checking

If A/C is not cooling properly, determine if the refrigerant system is fully charged.

If refrigerant system is low or empty, a leak at any points of the line fittings or component seals is probable. To detect a leak in the system perform one of the following procedures as designated by the symptom.


Empty Refrigerant System Testing



Evacuate the refrigerant system to the lowest possible degree of vacuum. Listen for vacuum leaks during evacuation.

Prepare a 14 oz. refrigerant charge to be injected into the system.

Connect and dispense 14 oz. of refrigerant (R-12) into the evacuated refrigerant system.

Proceed to Low Refrigerant Level Leak Test.








Low Refrigerant Level Leak Test








Position the vehicle in a breeze-free servicing area. It will be easier to detect a small leak.

With the engine shut off, use an "Electronic Leak Detector" and look for leaks in the most accessible areas first.


Fittings, Lines and Components that appear oily usually indicate a refrigerant leak.

To inspect the evaporator core for leaks, it is possible to insert the detector probe into the recirculating air door opening near the right side cowl trim behind the instrument panel.

Individual manufacturers leak detector manuals describe test procedures also.

Areas of air conditioning plumbing to be checked are as follows:

1. Plumbing joints for suction
2. Plumbing joints for discharge
3. Liquid line hose connections
4. Liquid line metal tubing connections
5. Liquid line hose crimp connections

System components to be checked are as follows:

1. Filter-drier joints, including weld seams and sight glass
2. High pressure relief valve
3. Expansion valve joints, including power dome and Tail stock
4. Low-pressure switch
5. Capillary tube well to suction line brazed joint (if applicable)
6. Damped pressure cycling switch and fitting
7. All service port fittings - discharge and suction
8. High-pressure cut-out switch and fittings (if so equipped)
9. Condenser - along vertical edges of end plates

Compressor points to be checked as follows:

1. Compressor joints
2. Shaft seal
3. Through bolts
4. Oil plug
5. Housing joints
6. Plumbing connections
7. Plumbing attachment to the compressor

Evaporator points to be checked as follows:

1. Evaporator - through defroster outlet with the blower set at low speed

For vehicles with rear A/C:

Four additional line connections as well as along the length of those tubes and hoses.
Also check inside the rear outlets with the blower set on low.





NOTES



When checking for leaks, position tester probe under the component, because refrigerant is heavier than air.

Do not allow the leak detector probe to come into contact with liquids. Liquids mask leaks and shorten sensor life.

Do not perform leak detection in an area with excessive airflow.

Do not come into contact with windshield washer fluid, paint and mastic fumes, excessive dust, halogenated solvents, or other contaminants. Contact with these, causes risk of erratic instrument operation or false readings.