Thermostat device for a cooling system and a cooling system comprising said thermostat device

A thermostat device (8) for a cooling system in a vehicle. The device (8) includes a thermostat housing (15) enclosing a movably arranged valve body (16, 20, 34, 44). The valve body is configured to distribute coolant from a thermostat chamber (15a) to a radiator bypass line (9) and/or a radiator (11) in dependence on the position of the valve body. The device (8) has a first thermal expansion element (31) providing a first stroke of a valve body (16, 20, 34, 44) in response to the temperature of the coolant in a the pilot chamber (14a), and a second thermal expansion element (32) providing a second stroke of the valve body (16, 20, 34, 44) in response to the temperature of the coolant in the thermostat chamber (15a) such that the valve body (16, 20, 34, 44) is moved to a position defined by the strokes from the thermal expansion elements (31, 32). The pilot chamber (14a) has an outlet passage (14b) for directing coolant from the pilot chamber (14a) to the thermostat chamber (15a).