Genuine OEM Nissan Radiator Cap, part number 214307996E. This radiator cap is designed to maintain the correct pressure within the engine's cooling system. By holding pressure, it raises the boiling point of the coolant, allowing the system to operate more efficiently and prevent overheating. The cap is located at the top of the radiator or expansion tank. Constructed from robust materials, this cap is built to withstand the thermal cycles and pressure variations of the cooling system. Genuine OEM radiator caps are precisely calibrated to ensure the cooling system operates at its optimal pressure, which is vital for engine longevity and preventing costly repairs.