GM Malibu/Cutlass 1997-2000

Thermostat

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REMOVAL & INSTALLATION




NOTE
When adding coolant, it is important that you use GM Goodwrench DEX-COOL® (orange colored, silicate free) coolant meeting GM specifications. On these vehicles, if silicated coolant is added to the system, premature engine, heater core or radiator corrosion may result. In addition, the engine coolant will require change sooner; at 30,000 miles (48,000km) or 24 months.


CAUTION
Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, 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 quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

2.4L Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Properly drain and recover the coolant to a level below the thermostat.
  4.  
  5. Unfasten the cover-to-outlet pipe bolt, which is accessible through the exhaust manifold runners.
  6.  
  7. Raise and safely support the vehicle.
  8.  
  9. Disconnect the radiator and heater hoses from the outlet pipe.
  10.  
  11. Unfasten the outlet pipe-to-oil pan bolt and the cover-to-outlet pipe bolts.
  12.  
  13. Remove the thermostat, then clean the old gasket material from the mating surfaces.
  14.  



Click image to see an enlarged view

Fig. Exploded view of the thermostat removal and installation-2.4L engine

To install:

  1. Position the thermostat in its correct location, then install the cover-to-outlet pipe bolt. Tighten the bolt to 10 ft. lbs. (14 Nm).
  2.  
  3. Install the outlet pipe-to-oil pan bolt. Tighten the pipe-to-oil pan bolt to 19 ft. lbs. (26 Nm) and the pipe-to-transaxle bolt to 40 ft. lbs. (54 Nm).
  4.  
  5. Connect the radiator and heater hoses to the outlet pipe.
  6.  
  7. Carefully lower the vehicle.
  8.  
  9. Install the cover-to-outlet pipe bolt through the exhaust manifold runner.
  10.  
  11. Properly fill the cooling system, then connect the negative battery cable.
  12.  

3.1L Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Drain the cooling system, into a suitable container, to a level below the thermostat housing.
  4.  
  5. Remove the air cleaner assembly.
  6.  
  7. Remove thermostat housing-to-intake manifold attaching bolt and nut, then remove the housing.
  8.  



Click image to see an enlarged view

Fig. Remove the two housing-to-intake manifold bolts and remove the housing

  1. Remove the thermostat.
  2.  

To install:

  1. Clean all gasket surfaces completely.
  2.  
  3. Insert the thermostat in the intake manifold.
  4.  
  5. Attach the thermostat housing to the intake manifold.
  6.  
  7. Install the mounting bolt and nut. Tighten to 18 ft. lbs. (25 Nm)
  8.  
  9. Install the air cleaner assembly.
  10.  
  11. Connect the surge tank line to thermostat housing.
  12.  
  13. Refill the cooling system.
  14.  
  15. Connect the negative battery cable, remove the radiator cap, then start the engine. Allow the engine to run with radiator cap removed, until the upper radiator hose becomes hot (thermostat open). With the engine idling, add coolant to the radiator until the level is up to the bottom of the filler neck.
  16.  
  17. Install the radiator cap, making sure the arrows line up with the overflow tube.
  18.  

 
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