Who was it that said some thing along the lines of "... the only stupid question is the one not asked..."? Then again... they probably never had children
Seriously though, catch can = overflow tank.... more or less
If you have a radiator cap on the raditor, expansion tank, top hose etc and in the neck it has a hose that runs to another tank, you are good! If the car is overheating bad enough to fill up a decent sized overflow tank... you have probably pulled it into the pits already! What they don't want is the normal expansion of the coolant to be puking on the track all the time. If a system is completely full with no air bubbles it will spit a little here and there under normal operation.
Antifreeze is not good for traction!
