Can a Car Be Driven After Being Submerged in Water?

[Sophie]

It is advised not to drive or use a car after it has been submerged in water. It must be inspected and repaired before use. If the vehicle is submerged while stationary, the engine is generally not damaged. However, attempting to start and drive the vehicle out of the submerged area may cause engine damage. Vehicle Water Submersion Inspection and Repair: Engine Inspection: Check whether the engine cylinders have taken in water, as water ingress can bend the connecting rods and damage the engine. If it is determined that water has entered the engine, the spark plugs should be removed first to manually cut off the fuel supply and ignition systems. Then, use an electric motor to rotate the engine, allowing the water inside to be expelled. Check the fluids in various systems: Inspect the condition of the fluids in the vehicle's systems to prevent foaming, cloudiness, or other signs of fluid deterioration due to water ingress, which can lead to loss of lubrication. Additionally, water may carry sand particles, causing excessive engine wear. In such cases, the relevant components should be cleaned promptly, and the affected fluids should be replaced. Remove interior items: If the water level rises above the doors, water is likely to enter the cabin. Rainwater is not clean and contains many impurities. The post-submersion car interior becomes a highly humid greenhouse environment, ideal for mold growth. If the vehicle is not dried in time, mold spots can damage the fabric and leather materials inside the car.

[LeBrooke]

Flooded vehicles must never be driven immediately. With years of driving experience, I've seen many such cases. When the water level exceeds the center height of the wheels, water can enter the engine cylinders. Starting the engine causes the pistons to compress the water, and since water cannot be compressed, the sudden pressure surge can bend the piston rods or even cause the engine to seize, resulting in repair costs exceeding tens of thousands. The risk of electrical system short circuits from water immersion is high, such as ECU control unit burnout or battery short circuits leading to fires. Sudden engine stalls while driving can also cause accidents. I remember after last year's floods, someone tried to move their vehicle, only for the electronic systems to fail midway, nearly causing a collision. Safety comes first—in such situations, turn off the ignition and call for towing services to transport the car to a professional shop for inspection. Technicians will check for emulsified engine oil, soaked air filters, and clean carpets and interiors to prevent mold. Flood damage may seem hidden, but it corrodes the vehicle over time. Don’t amplify the losses by rushing to drive.

[ORonan]

When it comes to driving after water submersion, the key concern is the risk of engine water intrusion. If water enters the cylinders and you turn the key to start, the piston's upward compression stroke encounters strong resistance from the incompressible water, potentially causing instant damage to connecting rods or the crankshaft—a phenomenon known as hydrostatic lock. In severe cases, this may require an engine replacement. A wet air filter increases the likelihood of the engine ingesting water mist, exacerbating damage. Electrical components like sensors and control modules can short-circuit and burn out if submerged and powered on, leading to costly and time-consuming repairs. Water in the brake system also reduces stopping power, raising accident risks. Inspection steps: After water recedes, first check the dipstick—milky oil indicates fluid contamination; remove the air filter to assess moisture; disconnect the battery as a precaution. Never attempt to start until all checks are clear—prompt towing for professional inspection is the safest approach.

[EmilioAnn]

Don't even try it, driving a car after it's been flooded is too dangerous. I know someone whose car got waterlogged after rain. In a hurry to move it, he started the engine which made a sound and then got stuck. Towing and repairs cost him several thousand, with a bunch of parts damaged. Even worse, the power windows and dashboard were ruined, the carpets didn't dry completely and got moldy, creating a terrible smell. Water entering the electrical circuits causes rapid corrosion, leading to hidden problems with endless consequences. At this point, you should patiently wait for the car to dry. It's best to use a blower to remove moisture from the interior, then have someone carefully inspect the circuits and chassis before touching any switches. Don't risk your safety or others'; the lesson is profound.