How to Replace the Heater Core in a Plymouth Neon

To replace the heater core in a Plymouth Neon, you need to remove the HVAC unit housing and disassemble the unit in order to remove the heater core. If you have the proper equipment and knowledge, discharge your Plymouth Neon air conditioning system. If not, have a reputable mechanic do this for you before beginning the following steps.

Instructions

1

Disconnect the negative battery cable. If your Plymouth Neon is equipped with air bags, wait at least 2 minutes after disconnecting the battery cable before you proceed in order to eliminate the risk of accidental air bag deployment. Then remove the instrument panel from your vehicle.

2

Drain the engine coolant into a clean container. Tightly cover or seal the container and set it aside. Disconnect the heater hoses from the dash panel and plug the heater core outlets to prevent any residual coolant from spilling out. If your vehicle is equipped with air conditioning, refer to Tips section before continuing to Step 3.

3

Loosen and remove the three retaining nuts located on the dash panel of the engine compartment between the blower resistor and the heater hoses. Unfasten the right side retaining screw and remove the remaining nut which is located in the dash panel stud. Next, detach the blue one way connector from the plenum; make sure to remove the module wiring harness along with the HVAC module.

4

Remove the HVAC unit from the vehicle. Then remove the clips and screws that secure the air distribution module to the evaporator/blower and separate them. Working with the air distribution module, remove the panel opening foam seal, demister opening foam seal, and the heater core tube foam seals.

5

Unfasten the retaining clips and screws holding the upper and lower housings together. Place the unit upside down and separate the two halves. Lift the heater core out of the case and replace with a new one. Secure the upper and lower halves of the module with the retaining screws and clips, then reinstall the seals you removed in Step 4.

6

Reconnect the air distribution module and the evaporator/blower and secure them, then install the unit housing in your vehicle. Attach the blue one way connector to the plenum and make certain the wiring harness is properly routed. Reinstall the nut located in the dash panel stud and the right side retaining screw.

7

Reinstall the three retaining nuts on the dash panel of the engine compartment and reconnect the heater hoses. Refill the engine coolant reservoirs and run your engine, checking for proper climate control operation and coolant leaks. If your vehicle has air conditioning, make certain you have the proper tools and knowledge for recharging the system or have an authentic technician do it for you.