Chevrolet Full Size Cars 1979-1989

Thermostat

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REMOVAL & INSTALLATION





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Fig. Fig. 1 Loosen the water outlet elbow (thermostat housing) retaining bolts



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Fig. Fig. 2 Lift the thermostat housing from the engine for access to the thermostat



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Fig. Fig. 3 Grasp and pull the thermostat from the bore while noting its position for installation purposes

  1. Drain the radiator until the level is below the thermostat (below the level of the intake manifold).
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CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to 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. Some late model vehicles will contain 1 or more Thermal Vacuum Switches (TVS) threaded into the top of the thermostat housing. If so equipped, tag and disconnect the vacuum lines from the valves.
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  3. Loosen the retaining bolts, then remove the water outlet elbow (thermostat housing) assembly from the engine.
  4.  
  5. Grasp the top of the thermostat and withdraw it from the bore. If necessary, use a pair of pliers to grip the top of the thermostat and pull it from the opening. Note the direction of the thermostat which was facing the engine for installation purposes.
  6.  

To install:

  1. Clean the gasket mating surfaces on the water outlet elbow and the intake manifold.
  2.  
  3. Install the thermostat assembly into the bore in the direction noted during removal.
  4.  
  5. Install the water outlet elbow (thermostat housing) to the intake manifold. Use a new gasket when installing the elbow to the manifold. On later models the thermostat housing may have been sealed with RTV sealant. If so, place a 1 / 8 in. bead of RTV sealer all around the thermostat housing sealing surface on the intake manifold and install the housing while it is still wet.
  6.  

If the thermostat is equipped with a pin hole, be sure to install pin side facing upwards.

  1. Secure the thermostat housing using the retaining bolts.
  2.  
  3. If applicable, connect the vacuum lines to the TVS(s) as noted during removal.
  4.  
  5. Refill the engine cooling system, then start the engine and check for leaks.
  6.  

 
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