Does Revving the Engine in Neutral Gear Harm the Car?

[ColtonFitz]

Revving the engine in neutral gear can cause the following damages to the car: 1. Revving in neutral subjects the engine's moving parts to significant inertial forces, affecting the engine's reliability and lifespan. 2. When the car is in neutral, the engine does not output power. Rapidly increasing the engine speed by revving causes sudden acceleration of moving parts such as pistons and connecting rods, generating substantial acceleration and subjecting them to significant alternating loads. Additionally, the sharp rise in engine speed during revving can lead to inadequate lubrication in friction areas, increasing the risk of cylinder scuffing and bearing failure. 3. Prolonged revving in neutral can result in severe incomplete combustion. If the unburned fuel-air mixture ignites outside the cylinder, it may cause the vehicle to catch fire. Incomplete combustion also promotes carbon buildup, which can clog the catalytic converter, leading to abnormal high temperatures. These high temperatures may cause wiring to catch fire, with potentially serious consequences.