2G Thermostat housing neck bolt size?

[John Mark Dongon]

I accidentally overtightened and broke a bolt, the neck housing that covers the thermostat itself has 2 bolts, want to know the part # or size

 

[FIBA M - EC17PSE]

Its an M8, length unsure for oem but i swapped mine out for some 25 or 30mm length ones i believe. How did you break a steel M8 bolt in an alloy housing? I can only assume it was a corroded weak bolt to begin with as that shouls have stripped out the housings threads

 

[DSMPT]

1G MF241855 M8x1.25x25 Washer Assembled Bolt.
2G MF140025 M8x1.25x20 Flange bolt.