Installing a thermostat on a car (spare tire removed): 1 - hose to the expansion tank; 2 - thermostat; 3 - radiator drain hose; 4 - radiator supply hose; 5 - hose to the water pump inlet pipe.
One of the reasons for the engine taking a long time to warm up after starting and overheating during operation is a faulty thermostat.
The thermostat valve should open at a coolant temperature of 85-89°C.
The thermostat is interchangeable with the thermostat of the VAZ-2108 car.
The text is on the website: VAZbook
Start the engine and let it idle. Feel the radiator outlet hose with your hand - it should be cold. If the hose gets hot, the thermostat is faulty and needs to be replaced (thermostat valve does not close).
Warm up the engine to approximately 87°C (the coolant temperature gauge needle is approaching the red zone). When the arrow is 3-4 mm away from the red zone, the hose should start heating up. Otherwise, the thermostat is faulty (thermostat valve does not open) and it needs to be replaced.