A vehicle comprising: a driveline retarder ; a sensor coupled to the driveline retarder and configured to measure temperature data that is indicative of a temperature of the driveline retarder ; and a coolant diverter system including: a coolant diverter body having a coolant inlet opening , a driveline retarder outlet opening and a bypass outlet opening ; a valve positioned in the coolant diverter body , the valve configured in a first valve configuration to fluidly couple the coolant inlet opening to the driveline retarder outlet opening in isolation from the bypass outlet opening , the valve configured in a second valve configuration to fluidly couple the coolant inlet opening to the driveline retarder outlet opening and the bypass outlet opening ; and a valve controller electrically coupled to the sensor, configured to receive operation data regarding the driveline retarder , the operation data comprising the temperature data and configured to selectively place the valve in the second configuration in response to the operation data indicating that a braking event in which a pedal of the vehicle is depressed for more than a nominal amount of time and the temperature of the driveline retarder being below a predetermined temperature threshold. a driveline retarder ; a sensor coupled to the driveline retarder and configured to measure temperature data that is indicative of a temperature of the driveline retarder ; and a coolant diverter system including: a coolant diverter body having a coolant inlet opening , a driveline retarder outlet opening and a bypass outlet opening ; a valve positioned in the coolant diverter body , the valve configured in a first valve configuration to fluidly couple the coolant inlet opening to the driveline retarder outlet opening in isolation from the bypass outlet opening , the valve configured in a second valve configuration to fluidly couple the coolant inlet opening to the driveline retarder outlet opening and the bypass outlet opening ; and a valve controller electrically coupled to the sensor, configured to receive operation data regarding the driveline retarder , the operation data comprising the temperature data and configured to selectively place the valve in the second configuration in response to the operation data indicating that a braking event in which a pedal of the vehicle is depressed for more than a nominal amount of time and the temperature of the driveline retarder being below a predetermined temperature threshold. a coolant diverter body having a coolant inlet opening , a driveline retarder outlet opening and a bypass outlet opening ; a valve positioned in the coolant diverter body , the valve configured in a first valve configuration to fluidly couple the coolant inlet opening to the driveline retarder outlet opening in isolation from the bypass outlet opening , the valve configured in a second valve configuration to fluidly couple the coolant inlet opening to the driveline retarder outlet opening and the bypass outlet opening ; and a valve controller electrically coupled to the sensor, configured to receive operation data regarding the driveline retarder , the operation data comprising the temperature data and configured to selectively place the valve in the second configuration in response to the operation data indicating that a braking event in which a pedal of the vehicle is depressed for more than a nominal amount of time and the temperature of the driveline retarder being below a predetermined temperature threshold. <EOS>