Why Shouldn't You Coast a Car in Neutral Gear?
2 Answers
Here are the reasons why coasting a car in neutral gear is not recommended: 1. When coasting in neutral, the engine stops running, and the air compressor ceases to operate. Since the car frequently needs to brake, the compressed air in the air reservoir continuously depletes, which may lead to brake failure. 2. It can easily damage the transmission. Most transmissions use rolling bearings extensively. While coasting in neutral, the second shaft of the transmission rotates, but the constant-mesh gears do not. As a result, these gears cannot agitate the gear oil in the transmission, causing bearings (especially those positioned higher and relying on splash lubrication) to lack reliable lubrication, leading to premature wear of bearings and gears. 3. Some drivers, aiming to save fuel, depress the clutch and let the engine stall to coast. After descending a slope, they suddenly release the clutch pedal to restart the engine. At this point, power is transmitted in reverse: drive wheels → half shafts → differential → reduction gear → drive shaft → transmission second shaft → synchronizer → clutch. The sudden engagement of the clutch with the stationary flywheel subjects the clutch to enormous impact loads, which can easily damage the clutch friction disc.
I've been driving for many years and always avoided coasting in neutral, mainly for several reasons. The primary concern is safety. When in neutral, the car lacks engine braking, relying solely on brake pads for stopping, which increases braking distance. This is especially risky downhill or in rainy conditions, raising the chance of losing control and accidents. Economically, many mistakenly believe it saves fuel, but the engine still idles and burns fuel, actually increasing consumption. From a mechanical perspective, it harms the transmission, potentially accelerating wear and raising repair costs. Legally, some places prohibit it, making fines not worth the risk. In summary, based on experience, keeping the car in gear while coasting is safer and more economical, fostering good long-term habits.
