Thermostat device and cooling system

A thermostat device for a cooling system in a motor vehicle, which thermostat device comprises:

• an inlet duct for receiving cooling fluid that has been circulated through a combustion engine in the motor vehicle;
• an inlet opening for receiving cooling fluid from a pilot line of the cooling system;
• a first outlet duct, which is connected with the inlet duct and for conducting cooling fluid to a radiator in the cooling system;
• a second outlet duct, which is connected with the inlet duct and for returning cooling fluid to the combustion engine without the fluid passing through the radiator;
• a valve body, which is displaceable between various positions for regulating the flow of cooling fluid from the inlet duct to one or both of the outlet ducts;
• an axially displaceable valve rod on which the valve body is secured, a temperature-dependent activating element configured and arranged to cause displacement of axial positions of the valve rod and the valve body dependent upon temperature of the cooling fluid that is received by the inlet opening wherein;
• a connecting duct that extends in an axial direction through the valve rod for connecting the inlet opening with the second outlet duct;
• the activating element is configured to displace the valve rod and the valve body in one axial direction when heated and in an opposite axial direction when cooled;
• and
• the valve rod is configured in order to allow a transfer of heat to the activating element from cooling fluid that flows through the connecting duct inside the valve rod.