Is It Harmful to Park in P Gear Without Turning Off the Engine While Waiting?
2 Answers
Parking in P gear without turning off the engine is harmful. Here are some details about parking in P gear: 1. Hazards: Although the car can be turned off without shifting to P gear, doing so may damage the transmission and engine. It is recommended to shift to P gear before turning off the engine. The P gear mechanically locks the output shaft of the transmission to secure the vehicle, preventing it from moving. 2. Correct Procedure: The most suitable parking sequence for the vehicle is to first stop the car on a level surface, then shift from D gear to N gear, engage the P gear, and finally pull up the handbrake to complete parking before turning off the engine.
I often encountered similar cases when I ran an auto repair shop. Keeping the car in P gear without turning off the engine for a long time indeed poses risks. When the engine idles, the cylinder temperature remains low, leading to incomplete fuel combustion which easily causes carbon buildup—especially noticeable in today's direct-injection engines. The worst case I've seen was a car that idled daily for three months outside a shopping mall while waiting, with carbon deposits on the throttle body so thick you could scrape off chunks. Additionally, running the AC for extended periods keeps the compressor working continuously, causing extra wear on belts and bearings. Not to mention idling with the AC on in hot weather—the cooling fan runs nonstop, draining the battery extremely fast. Once, during a customer rescue, I found his battery completely dead after idling for two hours while waiting for his child's tutoring session. My advice: turn off the engine if idling exceeds 10 minutes, and avoid running the AC for more than half an hour if necessary.
