A small amount of water enters the engine air intake.
After the vehicle wades, water generally enters the engine cylinder through the intake manifold. During the intake and exhaust of the cylinder, the piston will generate negative pressure in the intake stroke and suck in a lot of air. When water does not pass through the air inlet, it cannot be compressed, so the engine will be filled with oil-water mixed liquid.
When the engine is running, it doesn't matter if the accumulated water doesn't reach the height of the exhaust pipe, because generally speaking, the exhaust pressure of the engine is enough to push the accumulated water away. However, when the engine is turned off, when the water on the road is higher than the exhaust system of the engine, the phenomenon of water backflow will occur. As for which cylinder it flows to, it depends on which cylinder's exhaust valve is open. In addition, due to the incompressibility of water, the piston motion stroke will be shortened, resulting in bending or fracture of the engine connecting rod. In extreme cases, the broken connecting rod will fly out and break through the cylinder block. Million car purchase subsidy