Can the car be started after the water recedes from the exhaust pipe?
2 Answers
Water has receded from the exhaust pipe and the car can be started. The reasons are as follows: The exhaust system generally consists of the exhaust manifold (header), exhaust pipe, flexible connection (bellows), catalytic converter, and muffler. The exhaust system is almost horizontally arranged along the chassis, but the exhaust manifold is connected to the engine, and its vertical position is higher than other components of the exhaust system. When water has just submerged the exhaust pipe, it cannot enter the engine cylinders. After the water recedes, the water level in the exhaust pipe will definitely drop again, meaning it will be farther from the exhaust outlet. At this point, starting the car will not cause water in the exhaust pipe to be sucked back into the engine. After the water recedes, pay attention to the following starting method: Ignite and start the car, but do not press the accelerator and let it idle. At this time, a lot of water will be discharged from the exhaust pipe until it no longer drips, which should not take long, about 8 minutes.
I once witnessed a friend’s car engine getting completely ruined after attempting to start it post-flooding—a lesson I’ll never forget. Even if the water recedes below the exhaust pipe, it doesn’t mean the internals are dry. Residual moisture can linger in the exhaust system, catalytic converter, or intake. Starting the engine then sucks in water, causing hydro-lock—seizing pistons and catastrophic damage. Repairs could cost tens of thousands, a total waste. My advice? After flooding, resist the urge to start the car. First, check the air filter for water signs, and ideally, have a pro inspect it thoroughly. When driving through water, go slow and keep RPMs high to prevent backflow—protecting your car protects your wallet.
