5.3. Thermostat

You make replacement of the thermostat on the cold engine. Besides, when carrying out any works near the fan for prevention of its any inclusion it is necessary to disconnect a wire from the negative plug of the rechargeable battery.

Study the preventions provided in section 2.
Disconnect a wire from the negative plug of the rechargeable battery (if it is not executed earlier).
For simplification of access to the case of the thermostat remove the ignition distributor.
Merge cooling liquid from the cooling system to the level corresponding to bottom edge of the thermostat. For this purpose turn off a stopper of a bulk mouth of a radiator and a drain stopper in its lower part. After discharge of enough cooling liquid screw a drain stopper.
Disconnect the top hose of a radiator from an exhaust pipe of the case of the thermostat.

Fig. 5.1. Cooling system elements: 1 – broad tank; 2 – gear belt; 3 – water pump; 4 – stopper of a bulk mouth of a radiator; 5 – perepuskny hose; 6 – radiator fan electric motor; 7 – radiator; 8 – relay of turning on of the fan; 9 – thermostat; 10 – fan thermoswitch

Turn out a thermoswitch of the fan of the cooling system (fig. 5.1).
Turn off two nuts and remove the thermostat case from the engine. It is possible to disconnect the hardened laying complicating removal of the case of the thermostat by means of the rubber hammer.

Fig. 5.2. Elements of fastening of the thermostat: 1 – top hose of a radiator; 2 – thermostat case; 3 – laying; 4 – thermostat; And – a pin (at installation of the thermostat it has to be directed up)

Note situation and take the thermostat from the case (fig. 5.2).
Before installation of the thermostat clear a surface of an exhaust pipe and the privalochny plane of the case of the thermostat of the laying remains.
On both parties of new laying apply a thin film of sealant.
Install the thermostat in the case and arrange laying so that the corrugated surface was directed towards the thermostat. Establish a cover and fix by bolts, having tightened them the required moment.
Put on a hose an exhaust pipe of the case of the thermostat and reliably fix by a collar. Make sure that the arrow on a hose is combined with a ledge on the case.
Screw a radiator fan thermoswitch.
Install the ignition distributor.
Fill in antifreeze of the corresponding concentration in the cooling system.
Connect a wire to the negative plug of the rechargeable battery and launch the engine.
Let's work to the engine at the removed stopper of a bulk mouth until the top hose of a radiator does not become hot (the thermostat is open).
In operating time of the engine idling add cooling liquid in a radiator to the lower part of a bulk mouth.
Establish a stopper of a bulk mouth.

Check of the thermostat
It is the best of all to check the thermostat after its removal from the engine. As a rule, at suspicion it is the most expedient to replace the thermostat with malfunction as its cost is low.
For check remove the thermostat.
In the presence of traces of strong corrosion and damages the thermostat is subject to replacement.
For check of operability of the thermostat suspend it on a thread in the glass vessel filled with water and heat water to boiling, at the same time the thermostat should not concern vessel walls. Control water temperature the thermometer. The thermostat has to begin to open at a temperature of 88 °C and at a temperature of 97 °C has to open completely. Otherwise replace it.
The thermostat which is not closed when cooling water is also subject to replacement.
Install the thermostat.