Replacing heater core in a 1995 Toyota 4Runner

The heater core is a small heat exchanger located inside the truck, similar to the radiator at the front of the truck. Coolant is circulated from the engine through the heater core and back to the engine. The heater fan blows fresh, outside air through the heater core; the air is heated and sent on to the interior of the truck. For Toyota Pick-ups/Land Cruiser/4Runner 1989-1996 check this reference repair guide...



Heater Core - REMOVAL & INSTALLATION
(see Figure 1)

1. Drain the cooling system.
2. Remove the heater unit assembly. Have alot of towels handy for the leakage of coolant that may spill into your interior.
3. Remove the fasteners securing the core to the unit, remove the plates and clamps. Pull upwards to remove the core from the unit.

1. Inspect the core fins for any blockage. Using compressed air, clean them.
2. Install the core into the unit placing the plates and clamps into position. Tighten the core screws.
3. Install the heater unit into the vehicle.
4. Fill the cooling system.

1. Discharge the A/C system (if applicable), using an approved recovery/recycling machine.
2. Remove the cooling unit (if applicable).
3. Drain the cooling system.
   

1. Disconnect the hoses to the heater core. Tag each one so that it may be correctly reinstalled.
2. On some models you will need to remove the glove box assembly. On others, the instrument panel and reinforcement.
3. At the heater case under the dash, disconnect the ductwork from the case.
4. Disconnect the heater control cables from the heater case. Lift the spring clip holding the control cable to allow the cable to be manipulated. Don't deform or crimp the cables.

1. Disconnect the wiring harness to the blower fan.
2. Remove the three or four bolts holding the heater case to the dash. Because the inlet tubes project through the firewall, the unit will not fall straight down. It will need to be pulled into the passenger compartment and then brought downward.
   

1. Lift the case into position and carefully place the inlet and outlet pipes through the firewall. Install the retaining bolts holding the case to the dash.
2. Connect the wiring harness to the blower fan.
3. Connect the control cables to their linkages. Each must be adjusted so that the motion of the dashboard lever causes the correct corresponding motion in the air door. Both the control lever and the door must reach maximum travel at the same time if full function is to be achieved.
   1. Set the dashboard control to FRESH. Lift the adjustment clip and adjust the air inlet cable towards the heater unit until the linkage is at its maximum travel on Pick-Up and 4Runner. For Land Cruiser, adjust the cable away from the case. Release the adjustment clip.
   2. Set the dashboard control to VENT (Pick-Up) or DEF (4Runner and Land Cruiser). Lift the adjustment clip and adjust the air flow control cable towards the heater unit until the linkage is at its maximum travel. Release the adjustment clip.
   3. Set the temperature control to COOL. Lift the adjustment clip and adjust the air mix control damper control cable away from the heater case until the linkage is at its maximum travel on . For Land Cruiser, adjust the cable towards the case.
4. Connect or reinstall the ductwork. Make certain each tube is firmly and completely fitted on its port. A light spray of glass cleaner serves as a good lubricant; don't use too much.
5. Install the glove box and/or instrument panel assembly.
6. Connect the heater hoses. Use new clamps.
7. Install the cooling unit (if equipped).
8. Refill the coolant, then charge the A/C system (if equipped).