I am looking to install a Fujimoto type drain valve in place of the stock radiator drain plug. I have successfully done this on my Subaru WRX which allows me to connect a plastic tube onto the fitting and drain the coolant without it going all over everything. I have searched but cannot locate this information. I am looking for the size screw fitting (ie. M10 x 1.25 etc) so I can order the correct size. I can't even seem to find a stock replacement either and I consider myself a pretty good researcher. Has anyone done this mod? or can you please let me know what the size is, Thanks!!!

 

It's a m8