JAAY.
a PITA for sure.. but it's the old story.. a $15 dollar replacement cap changed earlier would have prevented the stress and aggro !
we all do it; putting off those little, niggly things and then regret that we didnt do it when they cause a problem.
its no biggie.. look at it this way.. it's just caused the need to do a coolant replacement, which is a 5 year item anyway.