### Thermostat

#### REMOVAL AND INSTALLATION

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

NOTE: The thermostat is housed in the water outlet casting on the cylinder head on most models. On the 1995–97 GA16DE engines, the thermostat is housed in the water outlet casting attached to the water pump.

1. Disconnect the negative battery cable.
2. When cool, open the drain cock on the radiator and drain the coolant into a suitable drain pan.
3. 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.
4. Remove the water outlet and thermostat.

   To install:

5. Clean off the old gasket from the mating surfaces of the thermostat housing and engine block.
6. 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.
7. Install the water outlet and tighten the bolts.
   - GA16DE — 13–16 ft. lbs. (18–22 Nm)
   - SR20DE — 5–6 ft. lbs. (6–8 Nm)
8. If removed, install the exhaust air induction tube clamp bolts.
9. Install the upper radiator hose, close drain cock and refill cooling system.
10. Connect the negative battery cable.
11. Start the engine and check for leaks.

##### 2.4L (KA24DE) Engine

###### Altima

1. Disconnect the negative battery cable and drain the cooling system.
2. Remove the lower hose from the thermostat housing at the rear of the engine.
3. Remove the bolts that secure the thermostat housing and remove the housing from the engine.
4. Remove the thermostat from the engine.
5. Clean the gasket mating surfaces.

   To install:

6. Clean the gasket surfaces on both the cylinder block and the thermostat housing.
7. Apply liquid gasket to the thermostat housing. The gasket material should be 0.079–0.118 in. (2.0–3.0mm) wide.
8. Install the thermostat to the housing. Be sure to position the thermostat with the jiggle valve to the top of the housing.
9. Attach the housing to the engine.
10. Tighten the housing mounting bolts as follows:
    1. 6mm — 57–66 inch lbs. (6–8 Nm)
    2. 8mm — 12–14 ft. lbs. (16–19 Nm)
11. Using a new hose clamp, connect the lower hose to the thermostat housing.
12. Connect the negative battery cable and refill the cooling system.
13. Start the engine, check for leaks, and bleed the cooling system.

###### 240SX

1. Disconnect the negative battery cable.
2. Drain the engine coolant into a clean container so that the level is below the thermostat housing.
3. Disconnect the upper radiator hose at the water outlet.
4. Loosen the three securing bolts and remove the water outlet, gasket, and the thermostat from the thermostat housing.

   To install:

   NOTE: When installing the thermostat, be sure to position the jiggle valve upward.

5. Install the thermostat to the engine with the thermostat spring toward the inside of the engine.
6. Using liquid sealer, install the thermostat housing and tighten the mounting bolts to 61–66 inch lbs. (7–8 Nm).
7. Using a new hose clamp, connect the upper radiator hose to the thermostat housing.
8. Connect the negative battery cable.
9. Refill and bleed the cooling system. Start the engine and check for leaks. Allow the engine reach normal operating temperature then check coolant for the correct level.

##### 3.0L (VE30DE) Engine

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

1. Disconnect the negative battery cable.
2. Drain the cooling system to a level below the thermostat housing.
3. Disconnect the radiator hose from the water inlet housing.
4. 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.

   To install:

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

##### 3.0L (VG30E) Engine

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

1. Disconnect the negative battery cable.
2. Drain the cooling system to a level below the thermostat housing.
3. Disconnect the water hose from the water outlet housing.
4. 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.

   To install:

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

##### 3.0L (VQ30DE) Engine

1. Disconnect the negative battery cable.
2. Drain the cooling system from the radiator and both sides of the engine block.
3. Disconnect the radiator hose from the water inlet housing.
4. Remove the water inlet housing mounting nuts. Separate the water inlet housing from the engine.
5. Remove the thermostat from the thermostat housing.

   To install:

6. Clean the gasket mounting surfaces.
7. Install the thermostat into the thermostat housing with the thermostat spring facing toward the engine. Be sure to position the jiggle valve facing upward.

   Fig. 1: Positioning of the jiggle valve — 3.0L (VQ30DE) engine

8. Using a new gasket, install the water inlet housing and torque the water inlet housing mounting nuts to 74–99 inch lbs. (9–11 Nm).
9. Connect the radiator hose to the water inlet housing. Be sure to use a new clamp.
10. Refill the cooling system.
11. Connect the negative battery cable.
12. Start the engine, bleed the cooling system, and allow it to reach normal operating temperatures. After cooling, check for leaks and recheck the coolant level.

##### 1995–97 2.0L (SR20DE) Engine

NOTE: The engine thermostat is housed in the water inlet housing where the lower hose attaches to the engine block.

1. Disconnect the negative battery cable.
2. When cool, open the drain cock on the radiator and drain the coolant into a suitable drain pan.
3. Remove the lower radiator hose from the thermostat housing.
4. Remove the bolts that secure the water inlet to the thermostat housing and remove the thermostat.

   To install:

5. Clean off the old gasket from the mating surfaces of the thermostat housing.
6. When installing the thermostat, be sure to install a new gasket or apply liquid 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.
7. Install the thermostat and the water inlet housing.
8. Install the mounting bolts and tighten to 56–74 inch lbs. (6–8 Nm).
9. Install the lower radiator hose, close drain cock and refill cooling system.
10. Connect the negative battery cable.
11. Start the engine, check for leaks, and bleed the cooling system.

##### 3.0L (VG30DE and VG30DETT) Engines

1. Disconnect the negative battery cable.
2. Drain the coolant from both sides of the engine block and drain the radiator.
3. Remove the engine undercover.
4. Remove the lower radiator hose.
5. Remove the radiator shroud.
6. Remove the engine drive belts.
7. Remove the cooling fan, the fan coupling, and the water pump pulley.
8. Remove the nuts and bolts that secure the water inlet and remove the inlet assembly.
9. Remove the thermostat assembly from the water inlet.
10. Clean the gasket mounting surfaces.

    To install:

11. Using a new gasket, install the thermostat into the water inlet housing.

    NOTE: Be sure to position the thermostat with the jiggle valve facing upward.

12. Install the water housing and secure with mounting bolts/nuts. Tighten the nuts and bolts to 12–14 ft. lbs. (16–19 Nm).
13. Install the water pump pulley, cooling fan, and the fan coupling .
14. Install and adjust the engine drive belts.
15. Install the radiator shroud.
16. Using new clamps, install the lower radiator hose.
17. Install the engine undercover.
18. Refill the cooling system and connect the negative battery cable.
19. Start the engine, bleed the cooling system, and check for leaks.