What are the hazards of frequently revving the engine in neutral gear?
2 Answers
Frequently revving the engine in neutral gear has four main hazards. Here are the relevant explanations: 1. It subjects the engine's moving parts to significant inertial forces, affecting the engine's reliability and lifespan. 2. When the car is in neutral gear, the engine does not output power. Revving the throttle at this time causes the engine speed to rise sharply, and moving parts such as pistons and connecting rods undergo rapid acceleration, generating substantial acceleration forces. 3. The components are subjected to considerable alternating loads, and the forces on the piston, piston pin, connecting rod, connecting rod bolts, and crankshaft exceed those during normal operation. 4. It impacts the engine's reliability and lifespan. Since the engine speed rises sharply when revving, the lubrication of various friction pairs cannot keep up, easily leading to failures such as cylinder scuffing and bearing seizure.
I always avoid revving the engine in neutral while driving, as this habit can cause significant harm. When in neutral, the engine has no load, and if you floor the throttle, the RPM can surge to several thousand, leading to accelerated wear on internal components like piston rings, cylinders, and the crankshaft. These parts operate under high temperature and pressure, and insufficient lubrication can easily cause malfunctions. Fuel is also wasted needlessly, burning liter after liter and polluting the air, while the exhaust pipe emits more harmful gases. Over time, the engine noise increases, idle becomes unstable, and the repair bills will hurt your wallet. More importantly, if you accidentally press the throttle while shifting gears, the car may suddenly lurch forward, which is extremely dangerous. I recommend developing good habits—don’t randomly rev the engine at red lights—it’ll save you both hassle and money.
