2000 Mountaineer 5.0 thermostat housing bolt size?

[KDK241]

Does anyone know the size of the thermostat housing bolt for a 2000 Mountaineer 5.0? One of the bolt heads broke off and I can't find a replacement bolt anywhere. I knew things were going too smoothly

 

[allmyEXes]

Maybe a 5/16 " bolt with 18 threads per inch about an inch long or less and uses a 1/2" wrench or socket on the head of the bolt. But you have to get the broken one out first and clean up the bolt hole with the appropriate tap.
Tractor Supply has a good selection of bolts.