It's weird that they don't have capacity listings anywhere for technical specs....even on the Koyo website.

Here's this thread to hopefully give you an idea:

https://www.s2ki.com/forums/s2000-un...diator-886591/

I'd imagine numbers vary wildly between users depending on how they go about draining their system and what components they replace...I'd imagine the block, water pump, radiator hoses etc can hold a decent amount of coolant, so that's why you're seeing different numbers.


Also not completely related but I haven't seen a lot of people do this. The strip on the top of the OEM radiator is there for a reason; it's a seal that butts up against the radiator support and makes it so air can't escape upwards (air following the path of least resistance and all that) to aid in ensuring that as much air gets forced through the core as possible and isn't lost by being allowed a different path. Not sure how much this helps, but the part was relatively cheap so I figured if it was there stock, it should most likely remain.