I had a coolant leak that I could not track down for a while. Turns out it was at the plastic portion of the upper radiator hose where the cap is at. The hoses themselves where in great shape, but the connections to the plastic was where the leak was from. I ended up replacing the whole hose, but was there an easier/cheaper fix for this. Sucks that it was just a bad design. Luckily the easiest hose replacement I have had to do and the first "repair" ever on the D!