Nissan Maxima 1993-1998 Repair Guide

Thermostat

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REMOVAL & INSTALLATION



VG30E Engine

See Figure 1

It may be necessary to remove radiator shroud, coolant fan assembly and water suction pipe retaining bolts to gain access to the thermostat housing.

The thermostat is located at the front of the engine, directly above the water pump.

  1. Disconnect the negative battery cable.
  2.  
  3. Drain the cooling system to a level below the thermostat housing.
  4.  
  5. Disconnect the water hose from the water outlet housing.
  6.  
  7. Remove the water outlet housing-to-thermostat housing bolts. Separate the water outlet housing from the thermostat housing. Remove the thermostat from the thermostat housing.
  8.  

To install:


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Fig. Fig. 1: Thermostat mounting detail-VG30E engines

  1. Clean the gasket mounting surfaces.
  2.  
  3. Using liquid sealant, apply a bead to the water outlet housing.
  4.  
  5. Install the thermostat into the thermostat housing with the thermostat spring facing the hose and the thermostat pintle in the upward direction.
  6.  
  7. Install the water outlet housing and torque the water outlet housing-to-thermostat housing bolts to 12-15 ft. lbs. (16-21 Nm).
  8.  
  9. Reconnect the hose to the front housing.
  10.  
  11. Refill the cooling system.
  12.  
  13. Connect the negative battery cable.
  14.  
  15. Start the engine and allow it to reach normal operating temperatures; then check for leaks. After cooling, recheck the coolant level.
  16.  

VE30DE Engine

See Figures 2, 3, 4, 5, 6, 7 and 8

The thermostat is located at the rear of the engine, directly above the transaxle bell housing.



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Fig. Fig. 2: Thermostat mounting detail-VE30DE engines

  1. Disconnect the negative battery cable.
  2.  
  3. Drain the cooling system to a level below the thermostat housing.
  4.  
  5. Disconnect the radiator hose from the water inlet housing.
  6.  
  7. Remove the water inlet housing-to-thermostat housing bolts. Separate the water inlet housing from the thermostat housing. Remove the thermostat from the thermostat housing.
  8.  



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Fig. Fig. 3: Remove the inlet hose and the three inlet pipe bolts ...



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Fig. Fig. 4: ... then pull off the inlet pipe ...



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Fig. Fig. 5: ... and remove the thermostat from the housing



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Fig. Fig. 6: Use liquid gasket to form a seal on the inlet pipe



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Fig. Fig. 7: Aftermarket gaskets are also available

To install:
  1. Clean the gasket mounting surfaces.
  2.  
  3. Using liquid sealant, apply a bead to the water inlet housing.
  4.  
  5. Install the thermostat into the thermostat housing with the thermostat spring facing the thermostat housing and the thermostat pintle in the upward direction.
  6.  



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Fig. Fig. 8: Make sure the thermostat pintle is in the upward position

  1. Install the water inlet housing and torque the water inlet housing-to-thermostat housing bolts.
  2.  
  3. Reconnect the radiator hose to the water inlet housing.
  4.  
  5. Refill the cooling system.
  6.  
  7. Connect the negative battery cable.
  8.  
  9. Start the engine and allow it to reach normal operating temperatures; then check for leaks. After cooling, recheck the coolant level.
  10.  

VQ30DE Engine

See Figures 9 and 10

The thermostat on the VQ30DE engine is located on the front of the right cylinder head. The water inlet pipe and the thermostat are an integrated unit, and must be replaced as an assembly.



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Fig. Fig. 9: Thermostat mounting detail-VQ30DE engines

  1. Drain the coolant from the radiator and both sides of the cylinder block.
  2.  
  3. Remove the accessory drive belts and the idler pulley bracket.
  4.  
  5. Remove the water pump drain plug on the pump side of the engine.
  6.  
  7. Remove the lower radiator hose from the water inlet pipe/thermostat assembly.
  8.  
  9. Remove the 3 retaining nuts, and carefully pull the assembly away from the housing. Do not reuse the gasket.
  10.  

To install:


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Fig. Fig. 10: VQ30DE engines use an integrated thermostat/inlet housing

  1. Place a new gasket on the pump housing.
  2.  
  3. Place the thermostat assembly on the engine and tighten the nuts to 74.6-99 in. lb.(.086-1.14 Nm).
  4.  
  5. Install the lower radiator hose to the water inlet pipe/thermostat assembly.
  6.  
  7. Install the water pump drain plug on the pump side of the engine.
  8.  
  9. Install the accessory drive belts and the idler pulley bracket. Be sure to set them the tension properly.
  10.  
  11. Refill the engine cooling system to the proper level.
  12.  
  13. Start the engine and check for leaks around the thermostat assembly and hose connections.
  14.  

 
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