Pontiac Fiero 1984-1988 Repair Guide




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Fig. Fig. 1 Exploded view of the thermostat assembly-2.5L engines

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Fig. Fig. 2 Exploded view of the thermostat assembly-2.8L engines

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Fig. Fig. 3 Remove the radiator cap and withdraw the thermostat from the opening

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. When the engine is cool, drain the coolant from the radiator until the level is below the thermostat housing cap.
  3. Remove the thermostat housing cap, grasp the handle of the thermostat and gently pull upward.
  5. Remove the thermostat O-ring to replace with a new one.

To install:

  1. Apply suitable lubricant to the new O-ring. Install the thermostat into the housing by pushing downward. Be careful not to damage the O-ring.
  3. Install the thermostat housing cap. Refill the radiator with the specified coolant. Install radiator cap only half way (to first stop). Start the engine and warm up to operating temperature. Remove the cap with a large towel and check coolant level and add if necessary.