Can a Car Be Started If Water Enters the Exhaust Pipe?
3 Answers
The car exhaust pipe is a device installed between the engine exhaust manifold and the muffler to reduce vibration and noise, facilitate installation, and extend the lifespan of the exhaust muffler system, providing flexible connection for the entire exhaust system. Whether a car can be started if water enters the exhaust pipe depends on the amount of water ingress, which can be divided into the following two scenarios: 1. Small amount of water ingress, can start: The typical wading depth for cars is between 50-70 cm, and the position of the exhaust manifold is similar in height to the intake manifold. 2. Large amount of water ingress, cannot start: The end of the exhaust pipe has a muffler. If a large amount of water enters (e.g., due to backflow during wading or flooding when parked in low-lying areas and the engine is off), it can accumulate in some dead corners of the muffler, eventually leading to rust and perforation.
Last time I watched my neighbor's car half-submerged in water still attempt to start the engine forcefully, ending up with an engine overhaul costing over 30,000 yuan. Let me tell you, water entering the exhaust pipe is like water getting into a person's windpipe—starting the engine in this situation directly sucks water into the cylinders, causing 'hydraulic lock'. When the piston moves upward and encounters incompressible liquid like water, at best it bends the connecting rod, at worst it blows the cylinder outright. I once saw a water-warped crankshaft during a repair, twisted like a pretzel. If your engine stalls in floodwater, never give in to the urge to restart it—immediately shift to neutral, push the car to dry ground, or call a tow truck directly. Otherwise, even insurance might deny your claim.
Having worked on cars for over a decade, I've witnessed too many tragedies caused by starting engines in flooded conditions. It becomes dangerous when the water level exceeds 30 centimeters above the exhaust pipe. Water can flow back through the exhaust manifold into the cylinders, and when the piston hits the water column during operation, it's like slamming into a concrete wall. Last week, a Mercedes-Benz S-Class owner didn't heed the warning and started the engine right after the floodwater receded. The result? Four out of twelve connecting rods in the engine were bent, and the bill for removing and repairing the engine reached six figures. Remember, when water submerges the exhaust pipe, it forms a sealed water column inside. The negative pressure created during startup sucks water in faster than a water pump. In such situations, it's best to wait for professional help. Replacing a fuse costs just a few dozen bucks, but repairing an engine could cost you two months' salary.
