What is the incorrect statement about coasting downhill with the engine off?

[StMelanie]

About coasting downhill with the engine off, the incorrect statement is that coasting downhill utilizes the slope's potential to propel the vehicle forward without the engine working, which can save fuel and should be strongly advocated. Additional information: Engine-off downhill: When the engine is off downhill, the vehicle loses engine braking resistance, and the power steering system also loses its power source, making brake failure extremely dangerous. Do not turn off the engine or shift into neutral when going downhill. If the engine stalls and the vehicle is in neutral while going downhill, it can easily lead to loss of control and accelerated wear of the brake pads. Forced downshifting: Do not turn off the engine to save fuel on downhill sections. If the vehicle stalls abnormally, for manual transmission vehicles, forced downshifting can be chosen, or the handbrake can be gradually applied using a method of pulling tight, releasing, pulling tight, and releasing repeatedly to bring the vehicle to a stop.

[LeilaniFitz]

Regarding the misconception about coasting downhill with the engine off, I find it particularly absurd that some car owners believe it saves fuel. When the engine is off, the brake booster stops working, making the brake pedal as hard as a block of iron—requiring full body strength to slow down, and in emergencies, it becomes impossible to stop. Moreover, without the engine's drag force, the vehicle speed increases uncontrollably, relying solely on the brake pads, which can overheat and fail in minutes. Last month, while driving on a mountain road, I witnessed a coasting car nearly plunge off the guardrail. In fact, modern fuel-injected cars cut off fuel automatically when coasting in gear, resulting in zero fuel consumption, whereas turning off the engine only increases danger. If the battery drains, even power steering is lost, making the steering wheel immovable.

[EmmaLee]

Many people mistakenly believe that coasting downhill with the engine off can extend engine life, which is completely unfounded. After the engine suddenly shuts off, the oil pump stops working, and the crankshaft and cylinder walls may experience dry friction, actually increasing wear. Moreover, the transmission idles during coasting, leading to insufficient lubrication of the gear oil, and the clunking sound of the gears is heartbreaking to hear. The braking system suffers even more, with overheating causing brake fade, and if you can't stop, you'll crash. Once, while helping a neighbor inspect his brake discs, I found that he often coasted with the engine off, and the disc surfaces were all blue and warped from overheating. To protect your car, you should use engine braking by staying in a lower gear, which is both stable and doesn't damage the components.

[Destiny]

The most dangerous misconception I've heard is that coasting with the engine off improves safety—utter nonsense. With the engine off, ABS and stability control systems immediately fail, making it impossible to control the car on slippery rainy roads. Power steering disappears, leaving the steering wheel extremely heavy when turning, and you wouldn't have time to avoid falling rocks. The engine stopping means the alternator isn't working, relying solely on the battery power—even turning on the headlights could drain it. Plus, modern cars have many electronic components, and a sudden power loss could fry the ECU. If you really want to save fuel, use the start-stop function—at least the safety systems remain operational.