so let me get this straight... "Because the thermal efficiency of internal combustion engines increases with internal temperature the coolant is kept at higher-than-atmospheric pressure to increase its boiling point. A calibrated pressure-relief valve is usually incorporated in the radiator's fill cap. This pressure varies between models, but is typically 9 psi (0.6 bar) - 15 psi (1.0 bar)."

so the coolant in the radiator is pressurized to keep it cooler, and the radiator cap releases excess pressure at a certain point. the higher the 'bar', the more pressure is allowed in the tank... correct?

just wondering cuz where i live it's freaking hot, and these Nismo caps are only $30 at a place here... so is it worth it?

 

correct