Originally Posted by AccordX2Boost

ok, the vented cap vs non has nothing to do with whether you have a resevior or not. the vented cap is a safety feature where you can release all of the pressure before opening the radiator to add fluid. if i am not mistaken it had a red handle on top?,...right? don't get that piece of crap, get oem. every cooling system has to have an overflow system, when the temp get hotter the excess pressure and fluid has to go somewhere, when the car cools down it simply sucks it back in. the reason the caps are rated 16lbs is because when the pressure in the radiator get to 16lbs it let's any pressure over that,..out.