Toyota previa heater core replace - 1994 Toyota Previa

SOURCE: 1992 Toyota Previa van,Oil dripping onto exhaust manifold, replace head gasket? need a free manual!

The toyota previa uses a formed silicone gasket for the valve cover and the cover is held in place by metric shoulder bolts ( 10mm). The valve gasket leaks because you can't get enough preload on the bolts to re-seat the old gasket when it gets old and shrinks. The shoulder bolts only allow you to tighten the gasket enough to seat the shoulder on the bolt. If you continue to torque down the suspected bolts, you will snap the bolt off ( don't ask me how I know this ). You can either 1.)replace the old gasket with a new one or 2.) remove the existing bolts around the leak area and put in new metric bolts that do not have a shoulder. You may want to put in a small sleeve into the existing bolt hole but shorter than the thickness of the valve cover to account for the smaller diameter bolt. You can now torque down the bolt and get enough preload to seal the valve cover without removing the old gasket. Make sure you use a torque wrench ( in-lbs) or be very careful not to snap these small valve cover bolts.

SOURCE: where is the flasher on a 1994 toyota previa

The flasher is bolted to the firewall behind the right side of the instrument panel and you can't get to it from underneath the instrument panel. You will have to remove the center console fascia to get to the instrument cover screws and remove the instrument cover. Then you can get to the instrument holding screws and move the instrument panel out of the way. Either a service manual or AutoZone.com will have this information and pictures. Replace the flasher with a genuine Toyota flasher relay. The aftermarket relays might look like they fit but I have found out they don't work properly. The flasher is bolted to the firewall with a 13mm bolt. Take out the bolt and replace the flasher.

SOURCE: Replacing heater fan motor in a Toyota Previa

Removal & Installation It may be necessary to remove the upper radiator shroud to perform this procedure.

1. Open and support the hood.
   
2. Disconnect the negative battery cable and wait at least 90 seconds to proceed working on the vehicle.
   
3. Disconnect the power steering and coolant reservoirs.
   

Disconnect the coolant reservoir

4. Disconnect the coolant reservoir and power steering brackets from the side of the heating unit box.


Remove the coolant reservoir bracket from the side of the heater unit


Separate the power steering reservoir bracket from the side of the unit also

5. Remove the two bolts that attach the upper and lower portion of the heater box. 6. Disconnect the control cable on the side of the heater unit box.

Disconnect the control cable on the drivers side of the unit

7. Remove the eight nuts retaining the unit.


Remove the nuts (8) from around the heater unit


There are 4 nuts on each side of the unit

8. Disconnect the heater control valve bracket from the heater box.

9. Separate the top of the control box from the bottom.


Separate the upper case from the lower

SOURCE: 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.

To install:

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.

Fig. 1: Exploded view of the heater unit assembly-1996 4Runner shown





Heater Unit - REMOVAL & INSTALLATION
(see Figure 1)

Have alot of towels handy for the leakage of coolant that may spill into your interior.

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.
   

CAUTION When draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

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.
   

To install:

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).

Hope this help (remember comment and rated this).