Overheating may be caused by a burst radiator hose, a faulty water pump, blown head gasket, or a leaky radiator. If the engine begins to get hot you should shut it down. Severe overheating can lead to more costly repairs. Warning: Never open a hot radiator cap. Once the engine is cool, check the radiator and heater hoses. A leaking hose is an easy fix. If the radiator is leaking through the radiator fins, you will probably need a new radiator. One of the more complex scenarios is an internal engine leak. If the engine is leaking coolant internally the probable cause is a blown head gasket or cracked cylinder head.