Can a Car Still Run After Being Submerged in Water?

Hurricanes can take a heavy toll on the environment. When evacuations take place due to a storm surge, many people will often leave their vehicles behind. But can you rescue your car after it has been submerged? Let’s take a look at what damage can occur when a vehicle has been underwater.

A car partially underwater.
Flooded car | Getty Images

What happens to the engine

One of the first concerns after a car has been submerged for any length of time in the water is if it will even run. It’s not a good idea to try to turn the engine over immediately until the damage can be assessed. There is likely water in the engine, transmission, and fuel system, and this will only make matters worse. Especially in coastal areas, saltwater is even worse for the internal systems in a vehicle. 

One of the most important things to look for in a vehicle that has been flooded is the high watermark. You can find this by looking for a dirty water line. If the water only got to the bottom of the doors, chances are the engine is fine. However, if the floodwaters went past the hood, you are likely looking at many systems being damaged. While many modern cars are sealed very well, chances are there is water in the engine, which can warp the components making the engine stall. This is going to lead to extensive repairs.

Are cars totaled after being flooded

Depending on where the high watermark is on a vehicle will determine the likely cost to repair. If the car was completely submerged, it’s expected that the insurance adjuster will total the vehicle since it will cost more to repair than the vehicle is worth. Not only is the engine likely damaged, but there are also hundreds of electrical components in modern cars. Most vehicles have computer modules. 

After being submerged in water, long-term, they will begin to fail and cause a multitude of hard-to-diagnose problems down the road. These systems depend on low-voltage signals from sensors in the engine management system and ABS. These low-voltage signals can be affected by corrosion build-up on connectors, causing problems that may not appear for years.

What is the best course of action for a flooded car

According to Popular Mechanics, one of the first things to do is clean out as much mud and water as you can. Again, don’t start the engine. It’s also a good idea to disconnect the battery to avoid further electrical damage. Next, check the dipsticks for the engine and transmission. If there are water droplets on them, it will be necessary to change the fluids and filters and possibly remove the oil pan if the water is muddy to clean the oil out.

Late-model vehicles have sealed fuel systems, so there is a slim chance that water infiltrates these systems. Muddy water can get past the engine seals in just a few hours. The seals are designed to keep fluids in, but they are not meant to keep fluids out. If possible, wheel bearings will need to be cleaned and re-packed. If the car continues to function, it’s also a good idea to change the fluids again after 1,000 miles.

Beyond these basic repairs, the engine may need to be completely disassembled and inspected for water damage. This may be cost-prohibitive, so it may not be worth the trouble if the water damage is extensive. Much of this will be determined by your insurance adjuster. Water can wreak havoc on a vehicle. It may be best left to the professionals to determine if your car is salvageable in the long run. 

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