Subaru Coupes/Sedans/Wagons 1985-1996 Repair Guide

Thermostat

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REMOVAL & INSTALLATION



See Figure 1

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Fig. Fig. 1: An example of a Subaru thermostat and housing


CAUTION
When draining the 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 the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

1.2L Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Drain the cooling system to a level below the thermostat housing.
  4.  
  5. Disconnect the upper coolant hose from the thermostat housing.
  6.  
  7. Remove the thermostat housing retainer bolts and remove the thermostat housing. If the housing is difficult to remove, tap it lightly with a plastic-faced hammer.
  8.  
  9. Remove the thermostat and gasket.
  10.  

Note the placement and direction of the old thermostat, so that the replacement unit is installed in the same way.

  1. Clean all gasket material from both mating surfaces.
  2.  

To install:
  1. Install the thermostat into the housing using a new gasket. Install the retainer bolts. Tighten the bolts to 7-9 ft. lbs. (9-12 Nm).
  2.  
  3. Connect the upper radiator hose to the thermostat housing.
  4.  
  5. Refill the cooling system.
  6.  
  7. Connect the negative battery cable.
  8.  
  9. Start the engine and bleed the cooling system.
  10.  
  11. Check for coolant leaks.
  12.  

1.6L, 1.8L and 2.7L Engines
  1. Drain the cooling system into a suitable container to a level below the intake manifold.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Disconnect the air intake duct and intake manifold hoses from the thermostat housing.
  6.  
  7. Loosen the hose clamp, and disconnect the upper radiator hose from the thermostat housing.
  8.  
  9. Remove the thermostat housing mounting bolts, then remove the housing and thermostat. Note the placement and direction of the thermostat for ease of installation.
  10.  

To install:
  1. Clean all gasket surfaces completely.
  2.  
  3. Install the thermostat in the intake manifold.
  4.  
  5. Using a new gasket, install the thermostat housing and tighten the mounting bolts to 7 ft. lbs. (10 Nm).
  6.  
  7. Connect the upper radiator hose.
  8.  
  9. Connect the air intake duct and intake manifold hoses to the thermostat housing.
  10.  
  11. Connect the negative battery cable.
  12.  
  13. Refill and bleed the cooling system.
  14.  
  15. Check for coolant leaks.
  16.  

2.2L and 2.5L Engines

See Figures 2, 3, 4, 5, 6 and 7

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Fig. Fig. 2: Loosen the radiator draincock ...



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Fig. Fig. 3: ... and drain the coolant into a suitable container



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Fig. Fig. 4: Loosen and remove the thermostat housing retainer bolts



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Fig. Fig. 5: Detach the housing to reveal the thermostat and gasket



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Fig. Fig. 6: Remove the thermostat and gasket assembly



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Fig. Fig. 7: Loosen the bleeder screw on top of the radiator to bleed air from the cooling system

  1. Drain the cooling system into a suitable container.
  2.  
  3. Remove the thermostat case cover located in the lower portion of the water pump. Remove the thermostat retainer bolts.
  4.  
  5. Remove the housing, thermostat and the gasket. Note the placement and direction of the thermostat for ease of installation.
  6.  

To install:
  1. For turbocharged models, install the thermostat with the jiggle valve at the 12 o'clock position.
  2.  
  3. For non-turbo models, install the thermostat with the jiggle valve facing down.
  4.  
  5. Install the housing with a new gasket, and tighten the bolts to 52-61 inch lbs. (6-7 Nm).
  6.  
  7. Fill and bleed the cooling system.
  8.  
  9. Check the system for coolant leaks.
  10.  

3.3L Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Drain the cooling system into a suitable container.
  4.  
  5. Disconnect the radiator hose from the thermostat housing.
  6.  
  7. Remove the thermostat housing mounting bolts.
  8.  
  9. Remove the thermostat housing, thermostat and gasket.
  10.  

To install:
  1. Install the thermostat and housing with a new gasket. Tighten the mounting bolts to 60 inch lbs. (7 Nm).
  2.  
  3. Connect the upper radiator hose.
  4.  
  5. Refill the cooling system.
  6.  
  7. Connect the negative battery cable.
  8.  
  9. Start the vehicle and bleed the system.
  10.  
  11. Check for coolant leaks.
  12.  

 
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