Utility vehicle

A utility vehicle, comprising:

• a cab;
• an engine including an engine coolant outlet and an engine coolant inlet;
• a heat exchanger including a heat exchanger inlet and a heat exchanger outlet;
• a heater core for heating the cab, the heating system including a heater core including a heater core inlet and a heater core outlet;
• and
• a coolant circuit, comprising:
• a first coolant line fluidly coupling the heat exchanger outlet to the engine coolant inlet;
• a second coolant line fluidly coupling the engine coolant outlet to the heat exchanger inlet and the heater core inlet;
• and
• a third coolant line fluidly coupling the heater core outlet to a bypass line, the bypass line fluidly coupled to a bypass valve assembly and the engine,
• wherein the bypass valve selectively couples the bypass line to the second coolant line based on a temperature of coolant at the bypass line.