Civic L4-1668cc 1.7L SOHC MFI (2003)
Heater Core: Service and Repair
Heater Unit/Core Replacement
SRS components are located in this area. Review the SRS component locations, and precautions and procedures in the SRS section before performing
repairs or service.
1. Make sure you have the anti-theft code for the radio, then write down the frequencies for the radio's preset buttons.
2. Disconnect the negative cable from the battery.
3. With air conditioning; disconnect the suction and receiver lines from the evaporator core.
4. From under the hood, open the cable clamp (A), then disconnect the heater valve cable (B) from the heater valve arm (C). Turn the heater valve
arm to the fully opened position as shown.
5. When the engine is cool, drain the engine coolant from the radiator.
6. Slide the hose clamps (A) back, then disconnect the inlet heater hose (B) and the outlet heater hose (C) from the heater core. Engine coolant will
run out when the hoses are disconnected; drain it into a clean drip pan. Be sure not to let coolant spill on the electrical parts or the painted
surfaces. If any coolant spills, rinse it off immediately.
7. Remove the mounting bolt and the heater valve as shown.