come to a head / bring to a boil
A crisis reaching its peak versus liquid reaching the boil.
Come to a head means a problem has reached the point of crisis. Bring to a boil is for liquid, or for raising feeling to a pitch. Do not mix the two. Bring to a head is the usual causative form of the first phrase.
Examples
Use The dispute came to a head on Friday.
Use Bring the stock to a boil.
Avoid The dispute came to a boil on Friday. (If you mean the crisis, not the metaphor of heat.)