Heater Core - Pressure Test

WARNING: This page is about a different car, the 2004 Mercury Mountaineer and 2004 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.

Use the Radiator/Heater Core Pressure Tester to perform the pressure test.

NOTE: Due to space limitations, a bench test may be necessary for pressure testing.

Clamp off the heater hoses.
Disconnect the heater water hoses from the heater core.
Install a short piece of heater water hose, approximately 101 mm (4 inches) long on each heater core tube.
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.

Fig 1: Identifying Tightening Torque Of Heater Water Hoses, Plug And Adapter With Hose Clamps
Courtesy of FORD MOTOR CO.
Attach the pump and gauge assembly from the Radiator/Heater Core Pressure Tester to the adapter.
Close the bleed valve at the base of the gauge. Pump 138 kPa (20 psi) of air pressure into the heater core.
Observe the pressure gauge for a minimum of three minutes.
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 perform the bench test.