Heater Core Bench Test
HEATER CORE BENCH TESTWARNING: Carbon monoxide gas is colorless, odorless and dangerous. If it is necessary to operate the engine with the vehicle in a closed area such as a garage, always use an exhaust collector to vent the exhaust gases outside the closed area. Failure to follow these instructions may result in personal injury.
NOTE: Testing of returned heater cores reveals that a large percentage of heater cores are good and did not require installation of a new heater core. If a heater core leak is suspected, the heater core must be tested by following the Heater Core Plugged Component Test, refer to HEATER CORE PLUGGED; before the Heater Core Pressure Test, refer to HEATER CORE PRESSURE TEST. Carry out a system inspection by checking the heater system thoroughly as follows:
1. Inspect for evidence of coolant leakage at the heater water hose to heater core attachments. A coolant leak in the heater water hose could follow the heater core tube to the heater core and appear as a leak in the heater core.
CAUTION: Spring-type clamps are installed as original equipment. Installation and overtightening of non-specification clamps can cause leakage at the heater water hose connection and damage the heater core.
2. Check the integrity of the heater water hose clamps.
3. Remove the heater core from the vehicle. For additional information, refer to HEATER CORE.
4. Drain all of the coolant from the heater core.
5. Connect the 101 mm (4 inch) test heater water hoses with plug arid adapter to the core tubes. Then connect the radiator/heater core pressure tester to the adapter.
6. Apply 241 kPa (35 psi) of air pressure to the heater core. Submerge the heater core in water.
7. If a leak is observed, install a new heater core, refer to HEATER CORE.