Use the Radiator/Heater Core Pressure Tester to carry out the pressure test.
1.
NOTE:
Due to space limitations, a bench test may be necessary for pressure testing.
Drain the coolant from the cooling system.
2. Disconnect the heater water hoses from the heater core.
3. Install a short piece of heater water hose, approximately 100 mm (4 in) long on each heater core tube.
4. Fill the heater core and heater water hoses with water and install Plug BT-7422-B and adapter BT-7422-A from the radiator/heater core pressure tester in the heater water hose ends.
Secure the heater water hoses, plug and adapter with hose clamps.
5. Attach the pump and gauge assembly from the radiator/heater core pressure tester to the adapter.
6. Close the bleed valve at the base of the gauge. Pump 138 kPa (20 psi) of air pressure into the heater core.
7. Observe the pressure gauge for a minimum of 3 minutes.
8. If the pressure drops, check the heater water hose connections to the core tubes for leaks. If the heater water hoses do not leak, remove the heater core from the vehicle and carry
out the bench test.
Heater Core — Bench Test
1. Remove the heater core from the vehicle. For additional information, refer to
Section 412-01
.
2. Drain all of the coolant from the heater core.
3. Connect the 100 mm (4 in) test heater water hoses with plug and adapter to the core tubes. Then connect the radiator/heater core pressure tester to the adapter.
4. Apply 138 kPa (20 psi) of air pressure to the heater core. Submerge the heater core in water.
5. If a leak is observed, install a new heater core.
A/C Evaporator/Condenser Core — On-Vehicle Leak Test
1. Discharge and recover the refrigerant. For additional information, refer to
Air Conditioning (A/C) System Recovery, Evacuation and Charging
in this section.
2.
NOTE:
DO NOT leak test an A/C evaporator core with the suction accumulator/drier attached to the core tubes.
Disconnect the suspect A/C evaporator core or A/C condenser core from the A/C system. For additional information, refer to
Section 412-01
.
3. Connect the appropriate test fittings from the R12-/R134a Air Conditioning Test Fitting Set to the evaporator or condenser tube connections.
4.
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 each 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.
Connect the red and blue hoses from the R134-a Manifold Gauge Set to the test fittings on the A/C evaporator core or A/C condenser core. Connect the yellow hose to a known good
vacuum pump.
5. 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 A/C evaporator core or A/C condenser core. If the refrigerant is not completely
removed from the oil, outgassing will degrade the vacuum and appear as a refrigerant leak.
6. 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
replacing the A/C evaporator core or A/C condenser core.
7. 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.
Page 44 of 45
2006 Town Car Workshop Manual
12/30/2011
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