The purpose of the engine cooling system is to dissipate heat generated by the combustion of fuel within the engine and maintain a favorable operating temperature to prevent damage and enhance engine efficiencies.
You wouldn’t change your oil without changing the oil filter, so why is it ok to put in a new radiator or add coolant and not replace the radiator cap and thermostat. Radiator caps and thermostats are essential for a properly functioning cooling system. They are two components that monitor the system parameters and adjust to maintain desired conditions.
The radiator cap monitors the pressure of the cooling system and constantly adjusts to maintain the desired pressure. Radiator caps can fail when the rubber seals become dry and develop cracks due to heat and low levels of coolant. The spring in the cap also wears over time and can get weak and leak coolant causing excess engine wear. This can happen between 50 to 60 thousand miles of use. If the radiator cap is not functioning properly, coolant can boil within the system causing severe damage to the engine and cooling system components.
Along with the Radiator Cap, the Thermostat also provides system monitoring and control making it a very important component of the system. The operation of the Thermostat is controlled by a sealed copper cup containing wax and a metal pellet. As the coolant heats the Thermostat, the wax expands pushing against pressure from a spring to open the thermostat and allow coolant to flow at the desired rate through the Radiator.
Cooling systems in today’s vehicles are becoming more and more complex as car manufacturer’s have learned they can improve fuel efficiency through improved cooling of the engine.
MotoRad recommends that you install a new radiator cap and thermostat whenever you change out any cooling system component. It is a rather small investment to insure the proper cooling system pressures are maintained.