Will Pouring Water into the Exhaust Pipe Damage the Car?
2 Answers
Generally, pouring water into the exhaust pipe will not cause engine damage. 1. Reason: When the engine is running, the exhaust pipe expels gases outward, creating no negative pressure to draw water in. Even if the exhaust pipe is submerged underwater, water will not enter. Engine damage only occurs if water enters while the engine is running. 2. Damage Mechanism: Since water is far less compressible than oil, a significant amount of water entering the cylinders under high pressure can easily break the engine's connecting rods or even puncture the pistons. It can also mix with engine oil, rapidly degrading its effectiveness, leading to cylinder scuffing. In such cases, the engine is essentially totaled.
I saw a friend trying to pour water into the exhaust pipe, and the car stalled immediately—what a scare! Water backflowing into the engine is no joke. The pistons in the engine cylinders normally compress air, but water is an incompressible fluid, leading to hydrostatic lock. When the piston pushes against it, it jams, bending the connecting rod or even deforming the crankshaft. I was there when they panicked and tried starting the car—only to hear a loud clunk as the engine was destroyed. The repair shop found the engine block cracked, and it ended up costing over 10,000 yuan to replace the engine. Remember, while exhaust pipes are designed with anti-backflow bends, manually pouring water can overwhelm them. Modern cars also have sensors, and water ingress can short-circuit the control unit. I always avoid driving through deep water during heavy rains—if the water level exceeds the exhaust pipe height, it’s dangerous. Car safety rule #1: Never let water enter the exhaust pipe, and definitely don’t pour water in for fun—the consequences are a major headache.
