So the coolant cap from the R8 goes on the coolant tank (most others as well) with the warning icon upside down and is keyed so you cant do much about it. So I figured out how to take it apart and fix it.

This type of pick tool or such goes in here:


Once you bend the outer lip of the top from the bottom. lift the bottom up and slide the the pick all of the way around it:


It should fall apart once you get all the way around it:


In the photo above you will also notice the tabs and tab voids are different sizes. That makes the top only fit on the bottom one way:


I used flush cutters to widen the bottom, more narrow notch so it was as wide as the other one:


Once you trim them to match, you can snap it back together in the opposite orientation. Fixed (but blurry):