I want to change my header coolant expansion tank on my MK Indy Fire Blade. The current one is leaking and too small, I am trying to replace it but the aluminium ones I have seen for sale only all only have two/three connection where as mine has four. 1. from the engine 2. top of radiator 3, bottom hose on a "T" junction and 4. overflow. Any ideas or suggestions where I might get a 1ltr/2.5ltr one please.

I've not seen any off the shelf ones with 4 pipes. Could the engine and rad pipes be Teed togther? If you can get it to three you are likely to have a lot more variety to choose from.