I have a 99 1500 (5.2L) 2wd. The radiator cap that's currently on the truck has a pressure relief valve attached to it. Is this stock? Should I replace it with a cap without a prv? A friend who helped me install the new rear end said he couldn't think of a reason for the PRV, since it has a res tank right beside the radiator. Is there a reason for the PRV? I wanted to get some other opinions before buying a new cap.

 

If the cap is the right pressure, and still works, don't worry about it. PRV is more for relieving pressure when the system is hot. (though, why you would want to is beyond me.)

If it ain't broke, don't fix it.