GReddy 13901002 Type S High Pressure Radiator Cap - JDM Spec GReddy High Pressure Radiator Caps are OEM style caps that directly replace the factory cap. GReddy radiator caps have a main valve pressure rating of 127kpa (1.3kgf / cm2) which allows for a higher boiling point. A higher boiling point ensures protection against over heating and also ensures your car maximum coolant flow at higher temperatures.