Genuine Nissan Maxima Heater Core

Nissan Maxima Heater Core Parts Questions & Answers

• Core Assy-Front Heater
  27140-40U00
  Q: How to replace the heater core on Nissan Maxima?

  A: Replacement of the heater core is a difficult procedure for the home mechanic, involving removal of the entire dashboard, floor console and many wiring connectors. If you attempt this procedure at home, keep track of the assemblies by taking notes and keeping screws and other hardware in small, marked plastic bags for reassembly. If the vehicle is equipped with air conditioning, have the air conditioning system discharged at a dealer service department or service station. Turn the heater control setting to HOT. Drain the cooling system. If the coolant is relatively new, or tests in good condition, save it and re-use it. Disconnect the cable from the negative terminal of the battery. Working in the engine compartment, disconnect the heater hoses where they enter the firewall. Remove the rubber grommets where the heater core tubes go through the firewall. Disconnect the air conditioning refrigerant lines and rubber grommet from the evaporator core if the vehicle is so equipped. Release the clip that retains the water control valve cable and disconnect the cable from the control valve. Push the cable through the firewall so it can be removed with the heater core housing. Lower the steering column and remove the entire instrument panel. Remove the instrument panel reinforcement bar. Where necessary for access, remove the floor heater ducting, the steel dash-to-floor braces, any remaining electrical connectors, then remove the PCM (computer). Unsnap the duct from the bottom of the heater core housing. Remove the evaporator core housing assembly or passenger side heater duct on models without air conditioning. Remove bolts/nuts securing the heater unit to the firewall. Disconnect the control cables from the unit. Pull down and back on the heater unit, making sure that all fasteners have been removed. Some twisting is required to separate the heater unit from the upper ducts. Remove the heater core from the heater unit. Reassemble the heater unit and check the operation of the control flaps. If any parts bind, correct the problem before installation. Reinstall the remaining parts in the reverse order of removal. When attaching the steering column to the support bracket, tighten the bolts or nuts. Refill the cooling system, reconnect the battery and run the engine. Check for leaks and proper operation of the system. Have the air conditioning system recharged if equipped.