Removal, check and installation of the thermostat

When the coolant temperature rises to a certain value, the thermostat opens a large circuit of the cooling system (through the radiator). If this doesn't happen (e.g. due to thermostat malfunction), the engine is overheating. This can be determined by the coolant temperature gauge on the instrument panel (he is in the red zone). At the same time, the radiator remains cold. If the thermostat does not close, the engine will not reach its operating temperature. At the same time, the arrow of the coolant temperature gauge rises more slowly than usual, and in winter the heating efficiency of the passenger compartment decreases.

Removing

Place a container under the thermostat to collect the coolant. Disconnect the coolant hose by loosening the clamp and sliding it.

Loosen the thermostat mounting bolts.

Attention! The thermostat is replaced complete with a drain fitting.

Examination

Attention! You can only check the beginning of the thermostat opening, since full opening occurs at temperatures above 100°C.

Hang the thermostat on a wire, place it in a container of water and gradually heat the water. The thermostat must not touch the walls of the container.


Start of thermostat opening: 92°C Full thermostat opening: 107°C

If not working properly, replace the thermostat.

Installation

Install the thermostat in place, putting a new sealing ring, and tighten the bolts of its fastening:

• for engines with a volume of 1.4 and 1.6 liters - a torque of 10 Nm,
• for engines with a volume of 1.8 and 2.0 liters - a torque of 15 Nm.

Connect the coolant hose and secure it with a clamp.

Diesel engine 17YD 1.7L

Removing

Place a container under the thermostat to collect the coolant.



Remove the cover from the thermostat housing by unscrewing the bolts and move it to the side along with the hose attached to it.



Remove thermostat with O-ring.

Installation

Install the thermostat with a new O-ring with the arrow pointing down.

Tighten thermostat cover bolts to 15 Nm.

TC4EE1 1.7L turbocharged diesel engine

Removing

Place a container under the thermostat to collect the coolant.

Disconnect the coolant hose from the thermostat housing cover.



Loosen the screws securing the thermostat housing cover.

Take out the thermostat.

Installation

Clean mating surfaces of thermostat housing and cover.



Install the thermostat so that the hole is on top.

Replace the thermostat cover with the sealing ring and fasten its fastening bolts with a torque of 30 Nm.

Connect the coolant hose and secure it with a clamp.

16-valve engines and turbocharged petrol engine

Removing

Open the cover of the expansion tank.


Place a container under the thermostat to collect the coolant.

Disconnect the coolant hose from the thermostat housing and drain the coolant.

Unscrew the bolts securing the upper part of the thermostat housing and remove it together with the thermostat.



Unscrew the thermostat from the clamps, squeezing it with tweezers, as shown in the figure.

Installation

Clean mating surfaces.



Install a new sealing ring.

Insert and fix the thermostat.

Tighten the screws securing the upper part of the thermostat housing.

Connect the coolant hose and secure with clamps.

Fill the system with coolant. Remove air from the system.