Heater Core - Bench Test
- Remove the heater core from the vehicle.
- Drain all of the coolant from the heater core.
- Connect the 101 mm (4 inch) test heater hoses with plug and adapter to the core tubes. Then connect the Pressure Test Kit to the adapter.
- Apply 138 kPa (20 psi) of air pressure to the heater core. Submerge the heater core in water.
- If a leak is observed, install a new heater core.