The reason why the engine still sounds after the car catches fire is:
 1. Cooling sound of the catalyst: the normal operating temperature of the catalyst is 400 to 800 degrees. After flameout, its operation will slowly stop, the temperature will also drop, and its internal metal parts will expand and contract with heat, and then make abnormal noise
 2. Turbine cooling sound: under normal conditions, the temperature of exhaust gas reaches 600 to 700 degrees, and the temperature generated by accelerating turbine rotation friction will also be obvious after flameout, resulting in abnormal noise.
 3. Uneven cooling of the engine: after the car has been driven for a period of time, the engine temperature is very high, and the temperature of all parts will drop after the car has stopped. It is impossible for the thermal expansion and cold contraction of all parts to be in full proportion, so it will inevitably or cause the cracks between the metal parts inside the engine to make abnormal noises due to friction due to cooling and contraction.