Hi everyone, I have a 99 BMW 540i, I added more coolant and did a bleeding because the low coolant light came on. So I noticed the bleeding screw goes all way down but will not tight hard, but not leaking, I bought a new bleeding screw, same thing it goes all way down but if you keep screwing it keeps turning but not too loose . The coolant tank is less than a month so new. I wonder if that is way it is supposed to be or I want to know if it should be screwed tight like any other screw, Any help is welcome
Thanks