Why Can't a Flooded Car Be Restarted?
2 Answers
A flooded car cannot be restarted because there may be water in the cylinders, and restarting could cause engine damage. If the engine is damaged due to a restart, it may not be covered by insurance. When a car is parked statically in deep water or driven through water, water can enter the engine's intake and travel through the intake pipes into the cylinders. Since the piston relies on compressing gas to achieve reciprocating motion, if liquid water enters the cylinder, it cannot be compressed by the piston. If the engine is restarted under these conditions, the piston will move upward to compress the water, but since water is incompressible, repeating this action can damage the piston or connecting rod, leading to a major engine overhaul. After driving through water, the second step is to call the insurance company to report the incident. Damage caused by flooding is typically covered under comprehensive auto insurance, and many commercial insurance policies now include free towing services within the city. It is necessary to inspect the extent of water ingress and damage. This includes checking whether the radiator fins are blocked, whether bearings are damaged by water, the condition of driveline components such as the driveshaft universal joint and CV joints, and the status of the chassis. Additionally, inspect the interior, floor, and whether water has reached electronic modules on the floor, testing their functionality. Check if water has entered the transmission vent and assess the transmission's condition. Also, examine the air filter, intake pipes, and cylinders for water ingress.
Once when I was driving home, I encountered a flood halfway and my car got submerged. In a hurry, I thought about restarting it to see if it could move, but my friend from the auto repair shop immediately shouted at me: 'Don’t be impulsive! A waterlogged car must never be restarted. The main issue is that the engine is prone to water ingress and seizing. Once water enters the cylinders, the piston movement can get stuck like a pump filled with water, not only damaging internal engine components but potentially rendering the entire vehicle a total loss. During inspection, it was found that fuses and wiring could short-circuit and catch fire, or even cause the battery to explode. So if your car gets submerged, first turn off the power, lock the doors, and evacuate safely. Wait for professionals to inspect it before taking any further action. As a reminder, always avoid parking in low-lying areas and try not to drive during heavy rain. Don’t assume restarting will save the day—it might just make things worse. Safety first is more important than anything else.'
