Does Water Entering the Exhaust Pipe Affect the Car?

[VonBethany]

Water entering the exhaust pipe can affect the car. Here are the detailed impacts: 1. It can cause serious consequences such as water entering the engine: If only the exhaust pipe has water, the accumulated water should be removed as soon as possible to prevent impurities in the water from clogging the three-way catalytic converter or damaging the oxygen sensor. 2. It may lead to exhaust pipe blockage: Poor exhaust can cause the engine to stall, but the engine may not necessarily take in water at this time. 3. Piston damage: Since water is far less compressible than oil, if a certain amount of water enters the cylinder under high pressure, it can easily break the engine's connecting rod or even damage the piston.

[VanCarson]

I was also curious about this the last time I washed my car. The exhaust pipe (what you call the 'chimney') actually has a drainage design—there's a small elbow at the tail end specifically to store water, so a little splashing from rain is completely fine. However, if the whole car goes through deep water, the situation becomes dangerous—if water rises above half the tire height, don't force your way through, as the engine might suck in water and stall. Even worse, if deep water floods the exhaust pipe and you try to start the engine, water can rush directly into the cylinders, potentially bending the piston rods! After driving through water, start the car and lightly press the accelerator to listen if the exhaust sounds smooth. There was a news story about a driver who forced their way through a water puddle and ended up spending over 20,000 yuan on engine repairs—a painful lesson indeed.

[OmarRose]

Having worked in car repairs for over a decade, I've seen too many flood-damaged vehicle cases. Water entering the exhaust pipe itself isn't a big deal—it might just cause rust or clog the catalytic converter. The real damage occurs when water backflows from the exhaust into the engine, known as 'hydrolock,' with repair costs starting at five figures. Once, a customer panicked after noticing continuous water dripping from the exhaust pipe while idling with the AC on after rain. In reality, it was just condensed water vapor from gasoline combustion, a normal phenomenon. But if the engine stalls in water and you attempt to restart it, even insurance won't cover the damage! My advice: if water levels exceed the centerline of the wheels, abandon the car immediately—life is more valuable than a vehicle.

[DeWalter]

New drivers often worry about water entering the exhaust pipe, but in fact, cars undergo rain tests before leaving the factory. What you really need to be wary of is the position of the engine air intake—as long as the water level doesn’t submerge it, you’re safe. Here’s a handy tip: after driving through water, don’t turn off the engine. Shift to neutral, rev the engine to 2,000 RPM, and the exhaust pressure will push out any accumulated water. My neighbor panicked last year during a heavy rainstorm and abandoned the car as soon as the water covered the exhaust pipe, resulting in a totaled vehicle. In reality, driving out slowly would’ve been perfectly fine. However, older cars require extra caution—if the exhaust pipe is rusted through, water could seep into the muffler and affect engine performance.