How High Does Water Need to Reach to Affect the Engine?
2 Answers
If a car is submerged above the tire level, it can cause problems. The biggest concern when a vehicle is submerged in water is the impact on the engine and electrical systems. Water entering the engine's air intake can directly affect the engine, and the electrical systems inside the car are also highly sensitive to water. Therefore, water should never exceed the tire level, as it can lead to water entering the cabin or the engine. The following components must be replaced if the vehicle is submerged: 1. Engine: If the vehicle does not stall or has not been started after being submerged, the engine oil, oil filter, air filter, and seals during the drainage process of engine components need to be replaced. If the engine stalls or is restarted, in addition to the above components, the engine connecting rods may need to be replaced depending on the situation, requiring an engine overhaul. 2. Transmission: Transmission fluid and transmission filter. 3. All vehicle fluids: If the vehicle is severely submerged, all fluids, including engine oil, coolant, power steering fluid, and brake fluid, must be replaced. 4. Bearing components: If the water level reaches the engine hood and the submersion time is prolonged, it is recommended to replace all bearing components to avoid rust, noise, and damage later on, such as the generator, air conditioning compressor, and wheel bearings.
A few days ago when my SUV was fording water, I paid special attention to the waterline. Basically, as long as the water didn't submerge the center cap of the tires, it was generally fine, provided I maintained a steady speed without going too fast. I once saw a friend's sedan stall with half its wheels submerged, and the repair shop later said water entered through the intake and bent the connecting rod. Now I always teach new drivers to check the exhaust pipe position—if water reaches the exhaust pipe opening, don't take the risk. A special reminder: intake heights vary widely between models. I've seen off-road vehicles handle 90cm water depth, while sports cars stall at just 25cm. Always manually turn off the auto start-stop function when fording water—an automatic engine restart can destroy it in seconds.
