For 1990-2009 cars

## Engine Coolant Thermostat Replacement 1.5L

### Removal Procedure

Warning: To avoid being burned, do not remove the radiator cap or surge tank cap while the engine is hot. The cooling system will release scalding fluid and steam under pressure if radiator cap or surge tank cap is removed while the engine and radiator are still hot.

1. Drain the coolant. Refer to Cooling System Draining and Filling.
2. Remove the timing belt rear hood.
3. Loosen the hose clamp on the upper radiator hose at the thermostat housing.
4. Disconnect the upper radiator hose from the thermostat housing.
5. Remove the mounting bolts that hold the thermostat housing to the cylinder head.
6. Remove the thermostat housing from the cylinder head.
7. Remove the thermostat from its recess in the cylinder head.
8. Inspect the valve seat for foreign matter that could prevent the valve from sealing properly.
9. Clean the thermostat housing and the cylinder head mating surfaces.

### Installation Procedure

1. Install the thermostat into the cylinder head recess.
2. Install the thermostat housing.

Caution: Refer to Fastener Caution in the Preface section.

3. Secure the thermostat housing to the cylinder head with the mounting bolts.

Tighten
Tighten the thermostat housing mounting bolts to 20 N·m (15 lb ft).

4. Install the timing belt rear hood.
5. Connect the upper radiator hose to the thermostat housing.
6. Secure the upper radiator hose to the thermostat housing with a hose clamp.
7. Refill the engine cooling system. Refer to Cooling System Draining and Filling.

## Engine Coolant Thermostat Replacement 1.2L DOHC

### Removal Procedure

Warning: Refer to Radiator Cap Removal Warning in the Preface section.

1. Drain the coolant. Refer to Cooling System Draining and Filling.
2. Remove the thermostat housing retaining bolts (1).
3. Remove the thermostat housing (2).
4. Remove the thermostat.
5. Inspect the thermostat for proper operation.
6. Clean the thermostat housing and the cylinder head mating surfaces.

### Installation Procedure

1. Install the thermostat into the cylinder head recess.

Caution: Refer to Fastener Caution in the Preface section.

2. Install the thermostat housing (2).

Tighten
Tighten the thermostat housing retaining bolts (1) to 10 N·m (89 lb in).

3. Refill the engine cooling system. Refer to Cooling System Draining and Filling.

## Engine Coolant Thermostat Replacement 1.4L LDT/1.6 LXV

### Removal Procedure

Warning: Refer to Battery Disconnect Warning in the Preface section.

1. Disconnect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection.
2. Drain the coolant. Refer to Cooling System Draining and Filling.
3. Remove the upper radiator hose from the thermostat housing.
4. Disconnect the thermostat wiring harness plug.
5. Remove the thermostat housing retaining bolts (1).
6. Remove the thermostat housing (2).
7. Inspect the thermostat for proper operation. Refer to Thermostat Diagnosis.
8. Clean the thermostat housing and the cylinder head mating surfaces.

### Installation Procedure

Note:

• | Do not use fallen parts. Plastic housing is very brittle and the fallen part may have internal crack that cause coolant leak.

• | Do not reuse rubber gaskets.

• | Check a coolant leak after the part replacement.

1. Fit the thermostat housing to the coolant distributor and use the NEW gasket.

Caution: Refer to Fastener Caution in the Preface section.

2. Install the thermostat housing (2).

Tighten
Tighten the thermostat housing retaining bolt (1) to 8 N·m (5.9 lb ft).

3. Connect the thermostat wiring harness plug.
4. Install the upper radiator hose from the thermostat housing.
5. Refill the engine cooling system. Refer to Cooling System Draining and Filling.
6. Connect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection.

## Engine Coolant Thermostat Replacement 1.4L/1.6L DOHC

### Removal Procedure

Warning: As long as there is pressure in the cooling system, the temperature can be considerably higher than the boiling temperature of the solution in the radiator without causing the solution to boil. Removal of the pressure cap while the engine is hot and pressure is high will cause the solution to boil instantaneously -- possibly with explosive force -- spewing the solution over the engine, fenders and the person removing the cap.

1. Drain the coolant. Refer to Cooling System Draining and Filling.
2. Disconnect the upper radiator hose from the thermostat housing.
3. Disconnect the throttle body coolant inlet hose from the thermostat housing.
4. Remove the thermostat bolts.
5. Remove the thermostat housing.
6. Remove the thermostat with the gasket.
7. Inspect the gasket for cracks or other damage.
8. Inspect the valve seat for foreign matter that could prevent the valve from seating properly.
9. Clean the thermostat housing and mating surface.

### Installation Procedure

Caution: Refer to Fastener Caution in the Preface section.

1. Install the thermostat with the bolts and the thermostat housing and tighten to 20 N·m (15 lb ft).
2. Secure the upper radiator hose to the thermostat housing with a hose clamp.
3. Connect the throttle body coolant inlet hose to the thermostat housing.
4. Refill the engine cooling system. Refer to Cooling System Draining and Filling.