What's the difference between a cooling system:1.catch can 2.recovery tank 3.expansion tank 4.overflow tank? I need to determine what I need for my system (it keeps puking out the overflow tube). I've been looking thru Jeg's, Summit,and Speedway and I see some are vented, some have a radiator style cap on top, some have a drain petcock on the bottom, etc. I know that expansion tanks need to be mounted at the highest point of the system so that's out (ugly). Should'nt the can be sealed so the vacuum will suck the overflow back into the system as it cools down? What are you running and how do you like it? Thank's in advance!