Why Should You Avoid Restarting a Flooded Car?
3 Answers
Restarting a stalled vehicle in water is considered a secondary ignition attempt, which can damage the engine. Here are precautions for driving through flooded road sections: 1. Assess water conditions: Pay attention to water depth. Observe other vehicles currently crossing to determine if your vehicle can pass safely based on their water levels and positions. 2. Check road surface conditions: Judge shallow areas and pothole-free zones by watching preceding vehicles. If no vehicles have crossed, always exit to personally verify conditions before proceeding. 3. Driving through water: Maintain low speed. For manual transmission vehicles, use second or third gear depending on water depth; shift to first gear in deep water with heavy traffic. 4. Avoid hard acceleration: Aggressive throttle application is highly inadvisable. Many drivers fear stalling and accelerate abruptly, often creating more serious problems.
Just heard a heartbreaking case from a repair shop friend a couple of days ago. Someone drove into a water-filled pit during heavy rain, stalled the engine, and then stubbornly tried to restart it, resulting in complete engine failure. Actually, when a car stalls due to water flooding, it means water has already entered the exhaust pipe or air intake, filling the cylinders with water. If you attempt to restart, the piston moves upward but can't compress the water, leading to a collision that bends the connecting rod. In severe cases, the entire engine may require major repairs. Even worse, if the vehicle's electrical system gets submerged and is then powered on, delicate components like the ECU and sensors can short-circuit and burn out. What might have been a simple drying-out job turns into a total loss. Water-damaged vehicles are no joke—wisely calling a tow truck is the smartest move.
Previously, I watched a car show conduct an experiment where water was poured into the engine intake to simulate a flooded vehicle. The moment the engine was restarted, the connecting rod bent into a V-shape. It's important to note that water in the cylinder cannot be compressed, and the piston's forced compression inevitably leads to metal deformation. More insidiously, electrical system damage can occur, such as the starter receiving power, which might cause the wiring harness to spark like firecrackers, frying all the vehicle's circuit modules. What could have been resolved by spending two to three thousand yuan to replace the intake system might end up costing the entire powertrain if forced ignition is attempted. Nowadays, insurance policies explicitly state that restarting a flooded vehicle is not covered, making this operation essentially a costly way to total the car.
