At what water depth will the engine be flooded?
4 Answers
When the water depth reaches the following conditions, the engine may be flooded: Sedans: For most sedans, when the water level exceeds 20 centimeters, there is a risk of engine flooding. SUVs: For SUVs with higher ground clearance, the risk of engine flooding occurs when the water depth exceeds 30 centimeters. The consequences of engine flooding are as follows: Engine connecting rod deformation: This leads to shortened piston stroke, preventing gases from being fully compressed. Piston leakage: The piston rings lose elasticity or fail to seal properly, causing gas leakage and compressed gases to enter the crankcase. Poor sealing: When the intake and exhaust valves do not close tightly, compressed gases leak into the intake manifold and exhaust manifold.
I've driven quite a few cars and believe water depth is crucial when it comes to engine flooding. Generally, when water depth exceeds the midpoint of the wheel hub (about 25-30 cm), the intake is prone to sucking in water, causing the engine to hydrolock. For example, my old sedan once stalled in knee-high water (around 30 cm), costing me 4,000 RMB in repairs. I've learned my lesson now: SUVs and off-road vehicles have higher intakes and can handle up to 40 cm of water depth, while regular sedans require extra caution—drive slowly through water to avoid creating waves. Before the rainy season, check engine seals, and if water does get in, don't start the car to prevent permanent damage. In short, the safest approach is to avoid deep water altogether—don't risk major damage for minor convenience.
As an enthusiast who loves studying car structures, I feel that water exceeding the height of the air intake will cause water ingress, with most cars at risk around 30 cm. The intake pipe is usually located under the hood or at the front of the car, making it easy to suck in water vapor when the water level rises. Once the engine locks, it's game over. I've seen some modified off-road vehicles that can handle deeper water, but standard sedans should never attempt it. Driving too fast or encountering water deeper than half the wheel height (about 25 cm) increases the risk. Water ingress repairs might involve replacing pistons and other parts, costing thousands. Always use tools to measure water depth beforehand—prevention is better than repair.
As a new driver, my friend taught me that the engine's water intake depth is usually around 20-25 cm. For example, if the water reaches the wheel rim edge, it's already dangerous. He once neglected a small puddle, and the engine got flooded and was scrapped, which scared me so much that I now stop directly at waterlogged roads. If water enters, stall and park, don't restart, as the repair costs are high. For prevention, remember the safety threshold: if the water depth exceeds the center of the tire, take a detour, especially for sedans.
