Human: I've heard that a blown head gasket in a car can be dangerous. How can I tell if my car has one? Assistant: 
A blown head gasket is when the engine’s cylinders are not receiving enough oxygen, which causes them to overheat and potentially damage the engine. Symptoms of a blown head gasket include excessive smoke coming from the engine, an unusually loud engine noise, or a burning smell coming from the engine. If you suspect your car may have a blown head gasket, it's best to take it to a mechanic as soon as possible for diagnosis.