It is known to provide a cooling system for cooling an engine of a motor vehicle. Cooling systems typically include a thermostatic pressure relief valve that controls the flow of coolant through a radiator of the cooling system in order to maintain the coolant, and therefore the engine, at an acceptable temperature. Thermostatic pressure relief valves are typically of the wax pellet type and arranged such that a valve permitting flow of coolant through the radiator is opened by thermal expansion of a wax pellet at a predetermined coolant temperature, the predetermined temperature being determined by the construction of the valve and thermal expansion properties of the wax pellet.
Known cooling systems suffer the disadvantage that under certain operating conditions the temperature of an engine may increase to relatively high values that result in relatively rapid deterioration of one or more components thereof such as spark plug tips, in the case of petrol engines, or one or more other components. For example, relatively sudden increases in the temperature of coolant at an engine coolant outlet can occur in the event a vehicle is towing a load downhill against a headwind in relatively high ambient temperatures with light throttle application and subsequently begins to climb a relatively steep hill with no headwind, possibly a tailwind, and relatively heavy throttle application. The cooling system may be unable to maintain the engine temperature within a preferred operating temperature range in these circumstances, resulting in excessive engine component degradation.
It is an aim of the present invention to address disadvantages associated with the prior art.