Attention: If the engine overheats after a short trip, the reason may be that the radiator is clogged with lime deposits.
Remove thermostat.
Slowly heat the thermostat in a container of water. In this case, the thermostat should not touch the walls of the vessel. The thermostat must be completely immersed in water. The temperature must be controlled with a thermometer.
At the opening temperature, i.e. around 85°C (for diesel engines - 70°С) The thermostat control plate should begin to open.
When cooling down, check if the thermostat closes completely. Otherwise, replace it.
Install thermostat.