Does a car being flooded mean it cannot be driven?

[LeDaisy]

Do not continue driving after the car has been flooded. If the vehicle stalls during the water crossing, do not attempt to restart it. There are three possible scenarios if you restart the engine, as detailed below: Air filter gets wet: The car can still be driven, but with water in the air filter, the engine will draw in some water into the intake tract, forming water vapor. This vapor mixes with gasoline and burns completely, having minimal impact on the engine. A small amount of water enters the engine: If a small amount of water enters the engine and mixes with the oil, the oil quality deteriorates. Oil containing water increases wear on engine components, potentially leading to increased engine noise and vibration in the future. The engine makes noise and stalls again after a few seconds: This is the most severe scenario. Since water cannot be compressed, when it enters the cylinder while the engine is still running at high speed, the inability to compress the water during the power stroke directly causes the valves and connecting rods to bend, the piston to seize, severe cylinder wear, and crankshaft bending. Replace the oil as soon as possible.

[DiBella]

Oh, I had a personal experience with my own car during a flood. The water reached halfway up the vehicle, and I thought I could slowly drive it out. But after just a few dozen meters, the engine gave up. The repairs ended up costing tens of thousands. A car getting wet doesn’t always mean it can’t be driven—for example, if it’s just tire splashes or shallow water and the engine bay is unaffected, you might manage for a short distance. But the risks are huge. Once water enters the exhaust system or air filter, the engine’s suction force can cause hydro-lock, leading to catastrophic failure, and electrical circuits may short-circuit or catch fire. My advice is to stop and turn off the engine immediately if you notice water intrusion—don’t attempt to restart it. Arrange for a tow or professional rescue to drain and inspect the vehicle. For daily parking, choosing higher ground can prevent this hassle. After water exposure, the interior is prone to mold growth, which affects health, and delays only make repairs more expensive.

[LaRicardo]

As a friend who often deals with similar incidents, it's best not to drive a car after it has been submerged in water, especially when the water level reaches the middle of the wheels. This can allow water to enter the engine or transmission system, causing irreversible damage. For example, water being sucked in through the air intake can lead to hydro-lock cylinder failure, rendering the entire engine useless, and replacing parts is both troublesome and expensive. If the electronic control unit gets soaked, it may short-circuit, potentially causing the entire vehicle to malfunction or creating safety hazards. I've personally inspected many vehicles, and the depth and location of water ingress are crucial: shallow splashes might be harmless, but deep water should never be attempted. Immediately stop in a safe location, turn on the hazard lights, engage the handbrake, and wait for the vehicle to dry before checking if the electrical circuits are functioning properly. For prevention, avoid low-lying roads during the rainy season, and installing an undercarriage waterproof cover can be effective.

[ReedLee]

Don't drive it! Forcing the car to move after water ingress is extremely dangerous - the engine could literally explode, and repairs would be both expensive and troublesome. I once encountered heavy rain and flooded roads while driving, but I didn't dare start the engine. I immediately called for rescue and had it towed away. If water enters the engine or electrical circuits, starting the car could cause short circuits that might fry the ECU or even trigger a fire. Shallow water might be manageable for slow maneuvering, but don't take the risk. After stopping, quickly remove the keys and open windows for ventilation to prevent damage to electronic components. Long-term water immersion also causes rapid depreciation, with moldy interiors creating health hazards and unpleasant odors. Remember: safety comes first - don't regret wasting a little time over this.