Can a Car Be Started When the Exhaust Pipe Is Submerged in Water?
3 Answers
Starting a car when the exhaust pipe is submerged in water is not advisable. Here are the detailed explanations: 1. Starting Hazards: If water has submerged the exhaust pipe, it may flow near the engine but won't enter the engine through the pipes. However, starting the engine in this condition can lead to water entering the engine, causing damage. 2. Handling Method: The vehicle should be pushed to a sloped area with the exhaust pipe facing downward. After positioning the car, wait for clear weather, open the engine hood to let it dry, and ensure there's no water inside the exhaust pipe before starting the engine. Listen for any abnormal engine noises; if everything sounds normal, the car can be used safely. It's crucial to wait until the vehicle is completely dry before starting to avoid water in the exhaust pipe being sucked into the engine.
You can start the car, but it's very risky. When the water level exceeds the exhaust pipe, starting the engine may force water back into the exhaust system or even flood the engine cylinders. The pistons in the engine compress air during operation, but water cannot be compressed. Forcing a start in such conditions can easily bend or break the piston rods, potentially destroying the engine. I've personally seen mechanics handle such failures—the entire repair cost can run into tens of thousands. Even if the car starts, driving with a water-clogged exhaust pipe may stall the engine, making it difficult to restart. So unless it's an emergency, never start a car in water. It's best to push it to dry ground first.
Theoretically, the car can start, but there are fatal risks. If water has submerged the exhaust pipe, it indicates a very wet environment. During startup, the exhaust is blocked, making the engine struggle to breathe, and the water temperature will rise abnormally. The biggest concern is water flowing back into the cylinders. When the pistons move up and down and suddenly hit the water—a hard obstacle—it can instantly destroy the engine. Additionally, the exhaust pipe contains expensive components like the catalytic converter, which will be ruined if flooded. The battery and wiring are also prone to short circuits when submerged. A friend of mine once ignored the risks and tried it, only to end up spending more on towing than engine repairs. In such situations, it’s better to pay for professional rescue rather than risk starting the engine.
