How to drain old coolant from the 5225 engine block?

[Creekpaddler]

I'm replacing the radiator hoses on my 5225 and have drained the radiator and the water pump. But I think some of the old coolant is still in the block. I've found one small threaded plug on each side of the block but I'm not certain what they are for. To get them out I have to use a 3/16" X 3/16" square-recess bit. That's a new one on me and I don't have a square bit that size.

Are these actually the coolant drain plugs? If they are, any suggestions for the right tool? If they are not the coolant drain plugs, can someone point me in the right direction? I haven't been able to find the info I need from Deere on-line.

 

[Zebrafive]

Those are oil passage plugs don't remove them

 

[Creekpaddler]

Zebrafive, thanks for the tip. I won't touch those plugs.