Does Revving the Engine in Neutral Harm the Car?
3 Answers
Revving the engine in neutral can harm the car, as it subjects the moving parts of the engine to significant inertial forces, affecting the engine's reliability and lifespan. When the car is in neutral, the engine does not output power. At this time, revving the engine causes a rapid increase in engine speed, and moving parts such as pistons and connecting rods undergo rapid acceleration, generating substantial acceleration forces and thus being subjected to significant alternating loads. The forces on the piston, piston pin, connecting rod, connecting rod bolts, and crankshaft will exceed those under normal operating conditions. Additionally, the rapid increase in engine speed during revving can cause inadequate lubrication in the friction pairs, making it highly prone to failures such as cylinder scuffing and bearing seizure. Therefore, revving the engine in neutral should be avoided. When in neutral, the gear lever can swing left and right. When the transmission is not engaged, the gear lever automatically remains in the neutral position.
Revving the engine in neutral can indeed cause damage to the car. While an occasional instance may not cause immediate harm, doing it frequently accelerates internal engine wear. When the engine is in neutral without any load, components like the crankshaft and pistons endure excessive pressure during high-speed rotation, leading to faster aging. I've seen many cars require major repairs due to this habit, with increased maintenance costs from oil seal leaks or bearing failures. Additionally, it's a complete waste of fuel—the fuel pump runs at full speed without any output, spiking fuel consumption and polluting the environment. In daily driving, avoid revving in neutral unless testing engine sound or warming up during a cold start. The key to protecting your engine is to keep it under load, which saves both hassle and money.
I've been driving for over a decade. In the past, when bored, I would rev the engine hard in neutral to pass the time, only to find that the car started slower. The mechanic found slight wear marks inside the engine and said fuel was burning rapidly. Now I understand that running the engine at high RPMs without connecting to the transmission system is just a waste of effort and damages the machine. Gasoline is consumed for nothing, and emissions exceed standards, which is not eco-friendly. So I've changed my habit and only press the accelerator when climbing hills or accelerating, avoiding neutral gear. This has saved me a lot on fuel and repair costs, and the engine runs more stably.
