Heater Core Leak Test Procedure TSB 89-14-9 for 88-89 Bronco, Aerostar, Bronco II, Ec
PUBLICATION DATE: July 14, 1989
1988-89 Crown Victoria, Escort, Festiva, Mustang, Probe, Taurus, Tempo, Thunderbird
1988-89 Continental, Cougar, Grand Marquis, Mark VII, Sable, Topaz, Town Car, Tracer
1988-89 Aerostar, Bronco, Bronco II, Econoline, F-150, F-250, F-350, Ranger
ISSUE Heater cores may be misdiagnosed and replaced unnecessarily. An inadequate seal between the heater core tubes can allow coolant to follow the tube to the heater core and appear as a leak.
ACTION If a heater core leak is suspected, use the following inspection and core leak testing procedure.
Look for evidence of coolant leakage at the hose to heater core attachments. A coolant leak at the hose could follow the heater core tube to the core and appear as a leak in the heater core.
Check the system for loose heater hose clamps. The clamps should be tightened to 16-22 lb.in. (1.8-2.5 N-m).
If leakage is found and the hose clamps are tight, check the heater core tubes for distortion or evidence of being bent out of shape. Severe distortion of the tubes by such things as over-torqued clamps could cause leakage at the hose connection.
Pressure Test - Heater Core In Vehicle
Drain the coolant from the cooling system.
Disconnect the heater hoses from the heater core tubes.
Install a short piece of heater hose (approximately 4 inches or 10 cm. long) on each heater core tube.
Prepare the heater core as follows:
Fill the heater core and hoses with water.
Install plug BT-7422-B and adapter BT-7422-A from Rotunda model 021-0012 or equivalent in the hose ends, Figure 1.
Secure the hoses, plug and adapter with hose clamps.
Air pressure test the heater core as described below:
Attach the pump and gauge assembly Rotunda model 021-0012 or equivalent to the adapter, Figure 2.
Close the bleed valve at the base of the gauge.
Pump 30 psi of air pressure into the heater core, Figure 3.
Observe the pressure gauge for a minimum of three minutes. The pressure should not drop.
If the pressure does not drop, no leaks are indicated.
If the pressure drops, check the hose connections to core tubes for leaks. If the hoses do not leak, remove the heater core from the vehicle and perform the bench air pressure test.
Pressure Test - Heater Core On Bench, Out Of Vehicle
Drain all coolant or water from the heater core.
Connect the four inch test hoses with the plug and adapter to the core tubes.
Connect the air pump and gauge assembly to the adapter, Figure 4.
Apply 30 psi of air pressure to the heater core with Rotunda model 021-0012 or equivalent.
Submerge the heater core in water.
If a leak is observed, service or replace the heater core as necessary.
OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: Information Only
OASIS CODES: 2600, 2620