Overheating, white smoke out of the exhaust if its gone between a coolant channel & cylinder, blue smoke if its gone between an oil channel & cylinder, overpressurised coolant system.
Its better if you tell us what symptoms you have

Coolant loss is most likly a fault in the coolant system, the plastic flanges on the front & RHS of the block are very comon sources of leaks. Then the rad, and also the header tank cap.
Check for white crusty deposits, especially along the plastic end caps of the rad. Its best to take the grill and the radiator fan shroud off so you can get a good look
