2002 SLK320 my coolant expansion tank has a little right angle pipe coming out from the neck below the cap. At a car show I met a Cross Fire owner with a similar engine and it had a tube attached to the pipe. I asked him if the tube went to a collection bottle of some kind and he said it just spills excess fluid onto his driveway and was somewhat annoyed he has to hose it off to protect animals from it. Is there supposed to be something to collect/return the overflow? Also on this forum I was told there is a flap in the expansion tank to prevent overfilling, mine has nothing like that, even put a finger in there and did a 360, nothing but the neck of the tank. I'm using the black plastic tank top as my fill line, does that sound right?