Why is an engine scrapped after being flooded with water?

[DominicMarie]

Because the engine combustion chamber is primarily designed to compress gases, not water. Water is a liquid, and once it enters, the force of the water will counteract within the engine, causing it to stall or severely damage the internal components of the engine, leading to the engine being scrapped. Below are precautions for driving through water: 1. Assess the depth of the water: If the water does not exceed half the height of the wheels, it is safe to drive; otherwise, it is not advisable to continue. 2. Use snow mode: After entering a waterlogged section, slow down and drive carefully. For automatic transmission vehicles, try to use first gear and preferably switch to snow mode to prevent wheel slippage. 3. Continuous braking: After exiting the waterlogged section, brake several times in succession to evaporate the moisture in the brake discs to avoid affecting the vehicle's braking performance.

[ArthurMarie]

I'm the type who loves to delve into cars. The main reason an engine is totaled after water intake is that water gets into the cylinders and can't be compressed. Imagine the engine at work: the piston moves up to compress the air-fuel mixture for ignition and explosion. Suddenly, if water is in there instead, it can't be compressed—it's like hitting a solid iron wall. The piston and connecting rod instantly bear excessive force, bending or breaking, and the crankshaft gets damaged too. Additionally, water causes short circuits in electronic systems like the ECU and sensors, frying the circuits and smoking upon startup. Repairs are a nightmare, often requiring complete replacements. The lubricating oil gets contaminated by water, turning into a milky emulsion and losing its protective properties, leading to accelerated wear or even seizing of metal components. Water also causes corrosion and rust, making internal metals brittle. Repair costs can easily run into tens of thousands, with potential lingering issues, making scrapping the car a more practical option. Prevention methods include avoiding deep water crossings, especially during heavy rain—steer clear of standing water and drive slowly. Once water is sucked in, it's game over.

[LaneAnn]

Last time I encountered this situation, my engine got flooded when driving through a puddle. After starting it, there was a loud bang and the car broke down. When towed to the repair shop and disassembled, the cylinder block was full of water stains. The technician said the piston compressed water instantly causing an impact, bending the connecting rod and damaging other parts. The electronic control unit short-circuited due to water ingress and threw errors, requiring a complete replacement. Combined with the cost of cleaning the fuel system, the expenses were shockingly high. I spent nearly twenty thousand and was still worried about potential rust hazards. Since the car was old and not worth much, I simply scrapped it for salvage. This incident taught me that repair costs after flooding are too high, and the risks make it better to abandon the vehicle. When driving through water, one must be careful not to accelerate or take a detour for safety. The engine's internal precision components are completely ruined by water immersion—don't push your luck and try it.

[VanGabrielle]

Simply put, when water enters the engine and causes it to be scrapped, it's because water is incompressible. Starting the engine immediately damages components. During the piston's compression stroke, it's supposed to compress gas, but water takes up space and can't be compressed, leading to bent connecting rods or even fractures, damaging the engine's core. Water conducts electricity, causing short circuits that burn out fuses and the ECU, resulting in control failure and rendering the car immobile. Oil mixed with water becomes diluted and loses its lubricating properties, accelerating friction and wear, generating excessive heat. Residual water causes rust, creating long-term hidden dangers and making repairs difficult to guarantee safety. Therefore, scrapping the engine directly saves hassle.