Radiator cap?
 

So I was going to replace my stock radiator cap. You on the stock one where you put it on then push it down for the last little turn then it stops??? well with the replacement one after i start turning it i hit that point then push it in for that last little turn it doesnt stop it just keeps turning then its back to where i have to push it in again and turn. So my question is if i push it in and turn it alittle till its tight, will it vibrate and turn to the point where its not tight again? Sorry I am not explaining this very well lol