As fuel prices rise, more and more drivers are trying to find ways to reduce consumption, so some are returning to an old habit - idling downhill.
At first glance, it sounds logical: if a car is powered by gravity, the engine should use less fuel.
However, this technique not only does not bring any real savings, but can also be dangerous, and in some countries even illegal.
Why idling is not a good idea
More harm than good
Contrary to popular belief, idling downhill actually uses more fuel than engine braking. In modern cars with electronic fuel injection, when you drive downhill at high speed with the accelerator pedal released, the computer completely cuts off the fuel supply to the engine. In this case, the wheels turn the engine, and consumption is literally zero.
On the other hand, when the transmission is in neutral, the engine has to run at minimum speed, for which it constantly needs fuel, writes Index.hr.
In addition to not saving fuel, this habit also causes increased wear on key vehicle components. Since you're not using the engine to slow you down, you're transferring all of the braking force to the brake system. This leads to faster wear on the discs and pads.
In a car with a manual transmission, holding the clutch pedal down for a long time while shifting to a lower gear creates unnecessary stress and can prematurely destroy the thrust bearing, making replacement a complicated and expensive process.
Safety first
The main reason for avoiding idling is safety.
Relying solely on the brakes when descending long, steep hills can lead to overheating and reduced efficiency, and in extreme cases, complete failure. Without engine braking, the car accelerates uncontrollably and the steering system can become less responsive, making it difficult to safely negotiate curves and react quickly in emergency situations, reports N1.
In many states, idling is also illegal. The law states: "The driver of any motor vehicle descending a hill on any highway shall not operate the vehicle idling with the transmission in neutral.
Although enforcement is difficult, modern cars are equipped with data recording devices that can detect this type of driving and help determine liability in the event of an accident.
Control the vehicle
An additional risk is the need to shift back into gear. In an unexpected situation, such as sudden braking from traffic in front of you or avoiding an obstacle, shifting from reverse to gear takes precious seconds.
Releasing the clutch suddenly at high speed can destabilize the vehicle and cause a dangerous loss of control. The unwritten rule is therefore, always control your vehicle with the gearshift, of course if you are driving a car with a manual transmission.
Bonus video:
