Coolant should be flushed around every 40,000 km or when it is due in the vehicle’s maintenance schedule.
Engine coolant contains anti-freeze, anti-boil and anticorrosive properties; however, over time these properties break down and sludge, scale and rust begins to form. In time, these formations clog the tiny passages within the radiator and heater, causing reduced coolant flow which in turn may result in poor interior cabin heating (in winter) and insufficient engine cooling and possible overheating (in summer)