Don't know off the top of my head. I would guess its about 3/8". I used the hose from my hand fluid pump. I didn't bother with the hose the several other times after this that I drained the coolant.
Yeah the cooling system is one of the know issues with the car. The other is everything related to the bullshit PCV design. I will be making a video on that at some point when all the parts arrive to hopefully alleviate all those issues finally.
