How Long Can a Car Stay in the Started State?
4 Answers
Several thousand hours. During fatigue testing, it can run continuously for thousands of hours. The key factor is the driver. Driving is a highly stressful task, especially for new drivers who may not know how to relax themselves. Therefore, driving continuously for 2 hours can be very tiring, while experienced drivers might not feel too fatigued even after 4 hours. Thus, it's best not to exceed 2 hours based on your own condition. Additional tips: Before setting off on a trip, conduct a comprehensive check of your vehicle. Ensure that lights, signals, horns, and rearview mirrors are complete and functional; check if the battery's charging and discharging are normal; pay special attention to the vehicle's braking system and tire condition. Additionally, bring along essential items such as a jack, tire wrench, fire extinguisher, and tow rope.
I've specifically tested this during long-distance driving before. A regular family car with a full tank can typically last about 500 to 700 kilometers, which translates to 5-7 hours at a highway speed of 100km/h. But in reality, it heavily depends on road conditions: if you're stuck in traffic with the AC on, the fuel gauge can drop twice as fast. Last time I drove on winding mountain roads with the engine constantly at high RPM, I could literally watch the fuel needle moving down. Also, a reminder—don't let your car idle for extended periods; exhaust fumes leaking into the cabin are no joke. If you really want to test the limits, remember to carry two spare fuel cans in the trunk—service areas aren't available every 50 kilometers.
As a hybrid car owner, I'd like to share a special situation. The engine actually starts intermittently while driving. When the battery is sufficient, it can run about 80 kilometers on pure electric power. However, when fully activated with both the motor and engine working together, it can last up to 900 kilometers with a full tank and full charge. But in actual tests, parking with the AC on consumes more fuel. The engine starts to recharge every 20 minutes, burning about 1 liter of oil per hour. It's advisable not to exceed two hours, as it's not very friendly to the three-way catalytic converter.
From a mechanic's perspective, the focus is more on damage issues. Ordinary cars should not run continuously for more than 48 hours. I've seen ride-hailing drivers sleep in their cars overnight, only to find the generator belt burnt with a scorched smell the next day. In fact, the engine cooling system is designed for wind cooling while driving, and idling in place provides particularly poor heat dissipation. Cast iron cylinder blocks may deform after more than 12 hours, and aluminum alloy cylinder blocks can't last a day either. The most serious issue is carbon buildup—3 hours of idling produces as much carbon deposits as driving 300 kilometers.
