Does Idle Start Hurt an Automatic Transmission Car?

[ChristopherAnn]

Idle start can indeed harm an automatic transmission car. During startup, the engine speed drops instantly, causing abnormal noises from the engine. The fuel cannot be fully burned, leading to carbon deposits. Correct procedure for starting an automatic transmission car: First, turn the key to the second position to allow the car's computer system to begin self-checking, which takes at least 5 seconds. Then, press the foot brake and shift the gear from P to N (for reverse, you can directly start the engine in P gear). After releasing the foot brake, turn the ignition key to the start position to fire up the engine. Next, press the foot brake, release the handbrake, and shift from N to D. For cars with a one-button start, press the foot brake and shift from P to D. Gradually release the foot brake to start moving. For prolonged idling in an automatic transmission car, shift to P gear. P gear is a special position that mechanically locks the transmission output shaft to secure the vehicle, functioning as a parking brake to prevent the car from moving.

[Figueiredo]

I've been driving automatic transmission cars for over a decade, and I believe idling starts generally don't harm the vehicle because modern transmissions are designed to provide slight creep in D gear to help the car move forward slowly. I start this way every morning in traffic jams and haven't encountered any issues. However, prolonged idling without moving wastes fuel and increases engine carbon buildup, so I recommend gently pressing the accelerator when starting to allow the transmission to transition smoothly, which is more vehicle-friendly. If you're idling without moving for extended periods, such as waiting in a parking lot for several minutes, it's better to shift to P gear to reduce unnecessary wear. Regular maintenance of transmission fluid ensures good system lubrication and prevents trouble. Overall, this is normal operation for automatic transmission cars, and there's no need to worry about damaging the vehicle, but developing good habits can extend your car's lifespan and save some fuel costs.

[McNaomi]

As someone who frequently repairs automatic transmissions, I can confidently say that starting from idle is safe and reliable, and won't directly harm the vehicle. This is because automatic transmissions generate a small amount of thrust through the torque converter or clutch plates at idle, helping the car crawl forward, which is particularly suitable for beginners to reduce the risk of rolling back. However, if the driver frequently accelerates aggressively from idle or repeatedly starts and stops in congested traffic, it may cause slight wear on internal clutch components, potentially affecting transmission efficiency over time. It's advisable to maintain smooth throttle control while driving, avoiding sudden acceleration, to ensure the longevity of transmission gears and belts. Additionally, regular checks of transmission fluid cleanliness and periodic inspections at a service center are recommended to prevent minor issues from accumulating. In summary, starting from idle is generally harmless; just avoid overuse to protect your vehicle.