Hella Meist 3 I purchased this to replace the OE extension antifreeze on MCS R53, the bad think is the cap design, Do I trust this yielding cap when pressurized? There is no explanation how many Psi this tank can hold the pressure when it is hot according to Mini Cooper cooling system to work , Something was worrying, The OE design Tank was without the AUXILIARY it will be great if the cap was the same as OE !After 2 weeks of testing in I put back the Original tank again, there is no MAX/MIN marked on this aluminum tank, No user guide ! It seems good but I hate this cap design ! Plus the broken little aux vent when screwing off ! I’m thinking to solder next !It should be good but why customer should re-design this for use !