What size bolts on the coolant flange?

[MastaFlyMason]

I took off my coolant flange and lost the bottom bolt, what size is it or where can I get one? Am I OK to drive with only 2, or will my oring get messed up? Thanks!

[ECS Tuning-Audi]

We can source them. What year is your 1.8T and engine code?

Jason