What are the causes for a blown head gasket?

First and formost Raidiator cap. Yes believe it or not start there then when you are having the heads fixed be sure to change the water pump its the second Major cause. Third is if your cooling fans stop working. Good Luck

Almost always overheating is the cause for whatever reason. Low of coolant, failed water pump, defective cooling fan, stuck thermostat, clogged radiator, etc.