What Happens When Water Enters the Exhaust Pipe?
2 Answers
If a small amount of water enters the exhaust pipe, it will gradually be expelled with the exhaust gases as the vehicle continues to be used, and it will not cause any noticeable adverse effects on the vehicle or the engine. However, if too much water enters, it can affect the engine, leading to stalling during operation. Waterlogged vehicles can be categorized into three scenarios: water submerging the exhaust pipe but not reaching half the wheel height, water just reaching half the wheel height, and water exceeding half the wheel height. Generally, water reaching half the wheel height can already affect the car. Water Submerging the Exhaust Pipe: If water only submerges the exhaust pipe, promptly moving the car away is sufficient. Water in the exhaust pipe will not be sucked back into the engine, and engine stalling is primarily caused by water entering the engine's intake system, not by the exhaust pipe being submerged. Water Just Reaching Half the Wheel Height: If water just reaches half the wheel height, the car usually won’t leak. However, if the car remains submerged for an extended period and the sealing strips have aged, leaks may occur. In such cases, drive the car to a 4S shop, dismantle the interior, clean it, and let it dry. Water Exceeding Half the Wheel Height: If water exceeds half the wheel height, the engine may take in water, and the interior may also leak. In this situation, never start the engine to avoid damaging the engine or electronic components inside the car. Additionally, if the car is waterlogged and starting it causes damage, insurance companies will not cover the costs.
That time I was driving in heavy rain and didn't pay attention when passing through a waterlogged area, causing water to enter the exhaust pipe. The engine immediately stalled, and after being towed to the repair shop for inspection, it was found that water had been sucked into the cylinders. This is called the hydrostatic lock effect, which damaged the pistons and connecting rods during compression, resulting in a complete engine overhaul that took almost a month and cost me several thousand. Looking back now, I still feel a lingering fear. Now when I encounter puddles while driving, I slow down or take a detour. A friend recommended installing a snorkel to raise the exhaust height, which really works. During regular maintenance, I also check the exhaust pipe connections to ensure they are well sealed to prevent water ingress. Never let the water depth exceed half of the wheel height—safety first, so the car lasts longer.
