Nissan Sentra/Pulsar/NX 1982-1996 Repair Guide

Thermostat

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REMOVAL & INSTALLATION




CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by 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.

E-Series and Diesel Engines

See Figures 1, 2 and 3



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Fig. Fig. 1: Thermostat and housing-E-Series engines



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Fig. Fig. 2: Thermostat and housing-Diesel engine

The engine thermostat is housed in the water outlet casting on the cylinder head.

  1. Open the draincock on the radiator and drain the coolant into a suitable drain pan.
  2.  
  3. Remove the upper radiator hose from the water outlet side and remove the bolts securing the water outlet to the cylinder head.
  4.  
  5. On E16 models, remove the exhaust air induction tube clamp bolts, then the water outlet bolts.
  6.  
  7. Remove the water outlet and thermostat.
  8.  

To install:
  1. Clean off the old gasket from the mating surfaces with a razor blade or equivalent.
  2.  
  3. When installing the thermostat, be sure to install a new gasket and be sure the air bleed hole in the thermostat is facing the left side (or upward) of the engine and that the spring is toward the inside of the engine. Also make sure that the new thermostat to be installed is equipped with an air bleed hole.
  4.  

CA16DE, CA18DE and GA16i Engines

See Figure 3



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Fig. Fig. 3: Always make certain the jiggle valve is facing upward when installing the thermostat

  1. Disconnect the negative (-) battery cable and drain the coolant from the radiator and the left side draincocks on the cylinder block.
  2.  
  3. On GA16i engines, disconnect the water temperature switch connector from the thermostat housing.
  4.  
  5. Remove the radiator hose from the water outlet side and remove the bolts securing the water outlet to the cylinder head.
  6.  
  7. Remove the thermostat and clean off the old gasket or sealant from the mating surfaces.
  8.  

To install:
  1. Install the thermostat with a new gasket. When installing the thermostat, be sure to install a new gasket or sealant and be sure the air bleed hole in the thermostat is facing the left side or upward on the engine. The jiggle valve must always face up. Also make sure the new thermostat to be installed is equipped with an a ir bleed hole. Some thermostats have the word TOP stamped next to the jiggle valve. Again, the word TOP and the jiggle valve must be facing up.
  2.  

When using RTV sealant instead of gaskets, make sure the surface you are working on is very clean before applying the sealant, then apply an even bead. Allow the RTV to dry slightly to form a thin skin. The component MUST be tightened before the RTV dries completely. The bolt torque should be checked again after RTV has completely dried.

  1. Install the water outlet and upper radiator hose.
  2.  
  3. On GA16i engines, connect the water temperature switch connector to the thermostat housing.
  4.  
  5. Fill the cooling system and connect the negative (-) battery cable.
  6.  
  7. Bleed the cooling system as outlined in this section.
  8.  

1.6L (GA16DE) and 2.0L (SR20DE) Engines

See Figures 4, 5 and 6



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Fig. Fig. 4: Thermostat and housing-SR20DE engine



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Fig. Fig. 5: Thermostat and housing-GA16DE engine



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Fig. Fig. 6: Always make certain the jiggle valve is on the top side-GA16DE engine shown

The thermostat is housed in the water outlet casting on the cylinder head on most models. On the GA16DE engines, the thermostat is housed in the water outlet casting attached to the water pump.

  1. Disconnect the negative (-) battery cable.
  2.  
  3. When cool, open the draincock on the radiator and drain the coolant into a suitable drain pan.
  4.  
  5. Remove the upper radiator hose from the water outlet side and remove the bolts securing the water outlet to the cylinder head and any other components in the way.
  6.  
  7. Remove the water outlet and thermostat.
  8.  

To install:
  1. Clean off the old gasket from the mating surfaces of the thermostat housing and engine block.
  2.  

When using RTV sealant instead of gaskets, make sure the surface you are working on is very clean before applying the sealant, then apply an even bead. Allow the RTV to dry slightly to form a thin skin. The component MUST be tightened before the RTV dries completely. The bolt torque should be checked again after RTV has completely dried.

  1. When installing the thermostat, be sure to install a new gasket and be sure the air bleed hole in the thermostat is facing upward and that the spring is toward the inside of the engine.
  2.  
  3. Install the water outlet and tighten the bolts.

    GA16DE-13-16 ft. lbs. (18-22 Nm)
     
    SR20DE-60-72 inch lbs. (6-8 Nm)
     

  4.  
  5. If removed, install the exhaust air induction tube clamp bolts.
  6.  
  7. Install the upper radiator hose, close the draincock and refill the cooling system.
  8.  
  9. Connect the negative (-) battery cable.
  10.  
  11. Start the engine and check for leaks.
  12.  

COOLING SYSTEM BLEEDING



See Figure 7



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Fig. Fig. 7: Many engines will have an air relief plug in the cylinder head or near the thermostat housing-SR20DE engine

The engine may be damaged if the cooling system is not bled. Air gets trapped in the cylinder head, causing a buildup of heat and pressure.

  1. Fill the radiator with the proper type of coolant.
  2.  
  3. Loosen the air relief valve in the cylinder head. Fill the engine with coolant until coolant spills out of the valve. If there is no valve, loosen a temperature sender that is nearest the top of the engine. Install the sender when coolant spills from the hole.
  4.  
  5. With the radiator cap off, start the engine and allow it to run and reach normal operating temperature.
  6.  
  7. Run the heater at full force and with the temperature lever in the hot position. Be sure that the heater control valve is functioning.
  8.  
  9. Shut the engine off and recheck the coolant level, refill as necessary.
  10.  

 
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