Mclaren F1 for your time.

Perhaps the most mundane post in the history of Oppo. But alas, I am trying to design a reservoir of around 2l for a project at work, and think that something along the lines of a coolant expansion tank would be ideal. Lots of inlets, outlets connectors etc. However I cannot for the life of me find a good explanation of how they are made. I’d assumed they were a blow mould but I’m doubting that given all the possible orifices in their design. Could any of you kind folk School me in the ways of Coolant Tank Design? This is the sort of thing I am thinking of: