Do not open the radiator cap and do not remove the thermostat until the engine has completely cooled down!
Removing
Petrol models
Models with SOHC engine
1. Disconnect the negative cable from the battery.
2. Empty the cooling system (contact the head Vehicle settings and routine maintenance).
If you are not going to add new fluid to the system, save the drained fluid for later use.
3. Remove the air cleaner assembly with air ducts (see chapter Power supply systems, release and reduction of toxicity of exhaust gases).
4. Loosen the mounting clamps and disconnect the upper radiator hose from the cover of the thermostat installed on the right side of the cylinder head.
5. Remove the timing case cover, timing belt with intermediate roller, camshaft gear and rear timing cover.
6. Remove the coolant hose from the thermostat housing, unscrew the fixing bolts and remove the thermostat cover. The thermostat is located on the side of the cylinder head, under the camshaft gear.
Bolts of fastening of a cover of the thermostat
7. Remove the thermostat from the housing, remove the sealing ring - try to remember the installation position of the components.
Models with DOHC engine
1. Disconnect the negative cable from the battery (see chapter Engine Electrical Systems).
2. Empty the cooling system (contact the head Vehicle settings and routine maintenance).
If you are not going to add new fluid to the system, save the drained fluid for later use.
3. On engines 1.0 and 1.2 l remove the air intake sleeve. Place a container under the thermostat cover fitting.
4. Loosen the mounting clamps and disconnect the upper radiator hose from the thermostat cover.
5. Turn out fixing bolts and remove the case together with the thermostat which is built in it. On engines 1.4 and 1.6 l remove the sealing ring.
Bolts of fastening of a casing of the thermostat of engines 1.4 and 1.6 l DOHC
Bolts of fastening of a casing of the thermostat of engines 1.0 and 1.2 l DOHC
Removing the thermostat seal
Diesel models
1. Remove the battery with support bracket (see chapter Engine Electrical Systems).
2. Apply the parking brake, jack up the vehicle and place it on jack stands. If equipped, remove the crankcase protection.
3. Empty the cooling system (contact the head Vehicle settings and routine maintenance).
If you are not going to add new fluid to the system, save the drained fluid for later use.
4. Loosen the mounting clamps and disconnect the upper radiator hose from the cover of the thermostat mounted on the cylinder head.
5. Turn out fixing bolts and remove a cover of the thermostat from the case.
Bolts of fastening of a cover of the thermostat
6. Remove the thermostat valve from the housing and remove the O-ring.
Examination
1. Before finally establishing your opinion about the failure of the thermostat, check the coolant level in the system, the condition and tension of the drive belt (see chapter Vehicle settings and routine maintenance), as well as the correct functioning of the temperature meter.
2. One of the possible reasons for the engine warming up too slowly (according to meter readings) is the thermostat sticking in the open position. Replace the thermostat with a new one.
3. If the engine overheats, feel the upper radiator hose with your hand. If the hose is not hot, the thermostat may be stuck closed, cutting off coolant circulation through the radiator. Replace thermostat.
Never operate the vehicle with the thermostat removed! This may break the feedback of the onboard processor, which will lead to increased toxicity of exhaust gases and an excessive increase in fuel consumption.
4. If the upper hose is hot, this means that the coolant is circulating through the radiator properly, i.e. thermostat is open. Refer to Section materials Troubleshooting.
5. The most accurate results are obtained by checking the thermostat on a workbench.
6. Remove the thermostat from the engine (see chapter Engines).
7. Tie a piece of wire to the thermostat assembly and lower it into a container filled with water. Lower the thermometer there as well.
Check of serviceability of functioning of the thermostat
Make sure that the thermometer and thermostat do not come into contact with the walls and bottom of the container!
8. Start slowly heating the water, watching the change in the thermometer readings - the thermostat valve should operate in strict accordance with the requirements of the Specifications in Chapter Engine cooling, interior heating and air conditioning systems.
9. Estimate the value of the full opening of the valve, - the nominal value is b - a = 8 mm.
Checking the completeness of the thermostat valve opening
Installation
1. Installation is carried out in reverse order. Pay attention to the following points the following.
- Thoroughly clean the mating surfaces and replace the sealing elements;
- Place the thermostat into the casing, orienting it correctly;
- Tighten the cover fastening bolts with the required force;
- Restore the original connection of all hoses and electrical wiring (where required, replace the removed sensors);
- Fill the system with coolant (contact the head Vehicle settings and routine maintenance);
- Start the engine, warm up to operating temperature and check for leaks.
On OHC petrol engines, the thermostat must be seated in the grooves
On diesel engines, the thermostat must be upside down
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