Heater Core: Testing and Inspection
Heater Core TestingPlugged Heater Core Test
1. Make sure the engine coolant is at proper level.
2. Start the engine and let it run to normal operating temperature.
3. Turn on heater and feel inlet and outlet heater hoses connected to heater core.
4. If inlet hose is hot and outlet hose is cooler, heater core may be plugged.
Leak Test
1. Inspect for visible evidence of coolant leakage at the heater hoses to heater core. A coolant leak at the heater hose could follow the heater core tube in the heater core and appear as a leak in the heater core.
2. Check the system for loose hose clamps. The clamps should be tightened to 2 - 3 N.m (2.5 - 3.7 kgf.m/18 - 27 lb-in).
3. If leakage is found and the hose clamps are tight, check the heater core tubes for distortion. Severe distortion of the tubes could cause leakage at the hose connection.
Pressure Test
1. Drain the coolant from the cooling system, then, disconnect the heater hoses from the heater core.
2. Install a short piece of hose approximately 101 mm (4 inches) long on each 3/4-inch heater core coupling, then connect couplings to heater core.
3. Fill the heater core and heater hoses with water and install plug and adapter in the ends. Secure the hoses, plug and adapter with hose clamps.
4. Attach suitable pressure tester to the adapter, then close the bleed valve at the base of the gauge and pump 207 kPa (30 psi) of air pressure into the heater core.
5. Observe the pressure gauge for a minimum of three minutes; the pressure should not drop.
6. If the pressure does not drop, no leaks are indicated.
NOTE
- Severe distortion of the core tubes could cause leakage at the coupling connection. Repair and replace as necessary. If pressure drops, check the coupling or hose connections to the core tubes for leaks. If the couplings or heater water hoses do not leak, remove the heater core from the vehicle and bench test the heater core.
Bench Test
1. Drain all coolant from cooling system.
2. Connect the 101 mm (4-inch) test heater water hoses with plug and adapter to the core tubes, then connect suitable pressure tester to the adapter.
3. Apply 207 kPa (30 psi) of air pressure to the heater core with pressure tester and submerge the heater core in water.
4. If a leak is observed, repair or replace the heater core assembly.