Is it harmful to rev the engine in neutral?
4 Answers
Revving the engine in neutral is harmful and can shorten the engine's lifespan. When the car is in neutral, the engine operates without any load. Suddenly pressing the accelerator in this state subjects some internal engine components to significant inertial forces, which can reduce the engine's longevity. If the engine is revved in neutral right after startup, it can accelerate engine wear. From a mechanical perspective, even though the gear is in neutral, the engine's power still drives the transmission's input shaft via the clutch, keeping it in an operational state. In this scenario, pressing the accelerator affects components like the input shaft, intermediate shaft, and constant-mesh gears, which adjust according to the engine's RPM, while the output shaft and synchronizers remain stationary. Prolonged revving in neutral or coasting long distances in neutral can damage the transmission, leading to issues such as input shaft bearing wear, synchronizer gear wear, burning, and transmission noise.
I've been driving for decades and often see beginners enjoying revving the engine in neutral, which actually harms the car. Running the engine at high RPMs without load is like a person running in place without moving forward—it increases internal component friction, leading to accelerated piston ring wear and cylinder overheating. Over time, fuel consumption also rises sharply. I remember a friend's car once suffered significantly reduced engine lifespan due to frequent neutral revving, eventually costing thousands in major repairs. I suggest avoiding this habit, especially at red lights, as it can also affect idle stability and throttle body contamination. If you encounter unusual noises or vibrations, it's best to visit a professional repair shop promptly for inspection.
I've repaired many cars myself, and revving the engine in neutral is definitely not a good idea—it causes significant damage to the engine. Engines are designed to idle at low RPMs, and suddenly flooring the throttle causes the RPMs to skyrocket, especially when exceeding 4,000 RPM. The resulting high temperatures and pressures accelerate the aging of seals and spark plugs, and in severe cases, can lead to cylinder scoring or even engine seizure. It also wastes fuel and increases emissions. From my experience, doing it occasionally is fine, but avoid prolonged periods, like when preparing for a high-speed run. Car maintenance manuals all recommend avoiding unnecessary high-RPM neutral operations because it disrupts proper engine load management. For the sake of your car's health, drive gently and perform regular oil and cooling system checks to prevent issues before they arise.
As an ordinary car owner, I understand that sometimes revving the engine in neutral is done to listen to the engine roar, but it is indeed harmful. High RPM without load increases engine wear, similar to how an idling chainsaw wears out the blade. Over time, this leads to higher fuel consumption and the noise also disturbs others. I tried it a few times and noticed a significant increase in my car's fuel consumption, not to mention having to change the oil earlier. Modern cars may have protective mechanisms, but it's not worth the risk. Instead of doing this, it's better to shift gears normally while driving to protect engine performance and save some money. In daily car use, avoid frequent such operations. If the car shows abnormal vibrations or other issues, promptly take it to a professional shop to check for transmission and electrical problems.
