HELP Thermostat fitting size???

[dirtbikeguy2003]

What tool do you use to remove the plug on the thermostat housing. I am setting up my coolant filter and i cant figure out what size it is. Looks like a sqaure but my 3/8 ratched doesnt fit.


Any help would be greatly appreciated.

Thanks

[bigcountrysg]

Should be an allen wrench of some size. I would try a 10mm allen wrench.

[dirtbikeguy2003]

Its a square. bigger than 1/4 ratchet but smaller then 3/8

[dirtbikeguy2003]

Its a 8 mm square drive for everyones information. Coolant filter kit all installed.