These gadgets usually come without any sort of instruction so you are supposed to know how, as an automobile enthusiast, to install them - wrong!!!
You have to open the cover, see which tube inside is the short one and then attach the radiator overflow line to it - the long tube inside dumps to the ground in case that tank completely overflows. If you hook it up the other way, goodby coolant (ask me how I know this
- yep, a senior moment).
Fill the radiator - the tank will just recover the fluid pushed out for whatever reason then it will eventually siphon back to the radiator as long as you have a pressure cap on the system