Testing Heater Core on B2300 Regular Cab 2WD L4-23L VIN A
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.
