A/C Evaporator/Condenser On-Vehicle Leak Test

A/C EVAPORATOR/CONDENSER ON-VEHICLE LEAK TEST

1. Discharge and recover the refrigerant. See Discharging And Recovery.

2. Disconnect the suspect evaporator core or condenser core from the A/C system.

3. Clean the manifold fittings.

4. Connect the appropriate test fittings from the A/C Fittings Set to the condenser or evaporator core tube connections.

5. Connect the red and blue hoses from the R-134a Manifold Gauge Set to the test fittings on the evaporator core or condenser core. Connect the yellow hose to a known good vacuum pump.


NOTE: The automatic shut-off valves on some gauge set hoses do not open when connected to the test fittings. If available, use hoses without shut-off valves. If hoses with shut-off valves are used, make sure the valve opens when attached to the test fittings or install an adapter which will activate the valve. The test is not valid if the shut-off valve does not open.

6. Open both gauge set valves and start the vacuum pump. Allow the vacuum pump to operate for a minimum of 45 minutes after the gauge set low pressure gauge indicates 101 kPa (30 in-Hg). The 45-minute evacuation is necessary to remove any refrigerant from oil left in the evaporator core or condenser core. If the refrigerant is not completely removed from the oil, outgassing will degrade the vacuum and appear as a refrigerant leak.

7. If the low pressure gauge reading will not drop to 101 kPa (30 in-Hg) when the valves on the gauge and manifold set are open and the vacuum pump is operating, close the gauge set valves and observe the low pressure gauge. If the pressure rises rapidly to zero, a large leak is indicated. Recheck the test fitting connections and gauge set connections before installing a new evaporator core or condenser core.

8. After evacuating for 45 minutes, close the gauge set valves and stop the vacuum pump. Observe the low pressure gauge; it should remain at the 101 kPa (30 in-Hg) mark.

- If the low pressure gauge reading rises 34 or more kPa (10 or more in-Hg) of vacuum from the 101 kPa (30 in-Hg) position in 10 minutes, a leak is indicated.
- If a very small leak is suspected, wait 30 minutes and observe the vacuum gauge.
- If a small amount of vacuum is lost, operate the vacuum pump with gauge valves open for an additional 30 minutes to remove any remaining refrigerant from the oil in the A/C evaporator core or A/C condenser core. Then recheck for loss of vacuum.
- If a very small leak is suspected, allow the system to sit overnight with vacuum applied and check for vacuum loss.

9. If the condenser core does leak, as verified by the above procedure, install a new condenser core. See Service and Repair.
If the evaporator core/TXV does leak, as verified by the above procedure, disconnect the TXV and recheck the evaporator core for a leak. If the evaporator core does leak, install a new evaporator core or condenser core. See Heater Core And Evaporator Core Housing Removal/Installation or Service and Repair. TEST the system for normal operation.
If the evaporator core does not leak, install new evaporator core/TXV seals and retest the evaporator core/TXV. If the evaporator core/TXV does leak, install a new TXV. TEST the system for normal operation.