Heater Core: Testing and Inspection

1. Disassemble the heater unit.
2. Check for cracks, damage, and coolant leakage. Repair or replace the heater core if necessary.
3. Check for bent fins. If they are bent, use a flathead screwdriver to straighten them.
4. Verify that the heater core inlet and outlet are not distorted or damaged. Repair with pliers if necessary.