How to Deal With Car Damage Caused by Flooding

Stephen Fogel
October 5, 2018

Hurricanes like the one that hit the Carolinas last month can leave vast amounts of destruction. We’ve all seen the photos of ruined homes, and cars with floodwater up to their roofs.

FEMA Flood
Image Courtesy of FEMA

So, what do you do if this happens to your vehicle?

Floodwater, and all the bad things in it, can create many different types of car problems. If your vehicle has been a victim of flooding or storm damage, it’s essential that you deal with it promptly, and properly.

Your safety always comes first

Perhaps the worst-case scenario would involve being in your car when severe flooding occurs. If you see water rising in an underpass or at an intersection, don’t enter it — find an alternate route or a safe spot to wait it out.

If you do end up in deep water, and your engine cuts out, here are some tips from the National Safety Council on what to do next:

  1. Remain calm and keep your seatbelt fastened to help steady you.
  2. Unlock the doors immediately.
  3. Open the windows (or just the ones at the high point of the vehicle, if it’s not level in the water).
  4. Remove heavy garments, such as coats, and keep your shoes on.
  5. Unlatch your seatbelt and exit the vehicle.
  6. Swim in the direction of the current.

If water rushes in and you can’t get out through the windows, don’t try to open the doors until the water level inside rises to your shoulders and the pressure equalizes.

If the windows and the doors won’t open, move to where the air pocket is inside the vehicle and try to kick out a side or rear window to escape. A hammer-type window-breaking device that you can keep in the car will make this easier.

Floods and engines don't mix

Engines are very susceptible to water damage. It only takes an average of 6 inches of water to reach the undercarriage of your car, and as it gets deeper, the risk to your engine increases. 

If water reaches the air filter housing, it may be sucked into the engine. Once that happens, the engine will stop running and internal components like connecting rods can get damaged. The best way to prevent this is to avoid driving through water that is deeper than the bottom of the front bumper.

If you drive your car in high water and it stalls, do not attempt to start the vehicle again — this can cause more severe damage. Once the vehicle is no longer submerged, disconnect the battery and have the vehicle towed to a repair shop. 

Checking your oil at this point is a simple way to start to assess how much damage has been done. If you see water droplets on the oil dipstick, or if the oil level is unusually high, water may have entered your engine. Don’t start the car until your mechanic has thoroughly checked it out.

The diagnostic and repair process from here will usually include the following steps:

  • Remove the air filter, clean out the housing and replace the filter.
  • Remove and clean or replace the spark plugs.
  • Drain and replace the oil and the oil filter.
  • Drain the transmission fluid, examine the pan and replace the fluid.
  • Check power steering, coolant, brake and clutch system for water infiltration; flush and replace as needed.
  • Let the entire vehicle dry out for a few days.
  • Reconnect the battery.
  • Crank the engine with spark plugs removed to get remaining water out of cylinders.
  • Let engine run for several minutes, then change the engine oil and oil filter again.
  • Change the oil and oil filter once more after 500 to 1,000 miles.
Get it diagnosed by a professional

Water in the fuel tank and line 

Water can also seep into your fuel line and fuel tank. Modern systems are sealed as part of the evaporative emission control (EVAP) system, but water can still work its way in. If it does get in the fuel system, the vehicle will either fail to start or it will run so poorly that it’s not drivable. 

Older cars with unsealed fuel systems, particularly those with carburetors, are more susceptible to water in the fuel system. Even after draining and refilling the gas tank, the performance of the car may slowly decline due to corrosion. 

If you think water got in the fuel system, drain the gas tank and refill with fresh fuel. Replace the fuel filter, as well. Make sure that the fuel lines are not clogged with silt and other debris, which is more likely if the floodwater was muddy. 

Flooding in the interior

Flooding in the engine or fuel tank is bad, but so is flooding inside the car’s interior. Your carpets and seats can get soaked with unsanitary water, and the wiring and electronics can be ruined.

It's important to quickly remove all the water, moisture and mud that you can. If water remains in the vehicle, mold can begin to grow and cause a whole new set of problems. 

Beginning with the seats and carpets, remove as much of the wetness and debris as possible and allow the interior to dry out. Use towels or dry rags to wipe down any wet areas. You can use fans or vacuums to speed up the process. 

Vehicles also have drain holes available underneath the carpet, but if you use them, they must be resealed when everything is dry. It’s also important to ensure that all windows are left halfway open, and the hood, trunk and doors are left open for further ventilation. 

Proper drying will prevent the formation of mildew, preventing any further damage. And don’t forget to remove, dry out and replace damaged items in your trunk.

Keep in mind that flood-damaged carpeting, upholstery, padding and door panels will likely need to be replaced once everything dries out. 

Electrical system: Trouble down the road?

It’s no surprise that a car’s electrical system can quickly get ruined by water. These problems can crop up immediately, or take days, months or even years to show up. This is the worst part of owning or driving a flood-damaged vehicle. 

To help identify issues right away, go through and check the operation of all the electrical systems in the car: headlights, air conditioning, radio, turn signals, locks, windows, seats — anything with an on/off switch. 

Also keep in mind that there are numerous electronic components buried behind trim panels, in the trunk, under the hood, and even under the seats. These components often suffer damage and can mimic issues with other systems. If you notice anything that is “off” about the car, have it checked by your mechanic to see if there is a flood-related electrical cause.

» LEARN MORE: Get an estimate for your car repair

Check the brakes

If you have to drive through high water, make sure to give your brakes a test before continuing on. The sediment in the water could cause them to fail momentarily. 

Also, if the water is deep enough to submerge the front wheels or master cylinder, it may be a good idea to flush the brakes. Water can enter the master cylinder brake fluid reservoir cap, severely decreasing your braking efficiency. This is much less common, but it's better to check just in case. 

Will insurance cover it?

If you have comprehensive auto insurance, which covers most types of damage to your vehicle other than crashes, you’re most likely covered for flood damage. Check your policy for the exact details. If you’re covered, then one of your first calls should be to your insurance agent. Do this as soon as possible — typically, you’ll have to file within 60 days, and if you’ve been hit with a huge storm, your insurer will likely have a lot of claims to sort through. 

Just as with a vehicle that was involved in a bad accident, your insurance company will look at how the cost of repairing the flood damage compares to the current value of your car. If the repair cost is more than that value, they may choose to total the vehicle and pay you what it’s currently worth. 

If you don’t have comprehensive insurance, it’ll be up to you to pay for repairs or replacement. If the vehicle is newer, you may be able to resell it with a “flood salvage” title. Another option would be donating it to a charity and taking the tax write-off. Just be careful when buying your next car — a lot of flood-damaged vehicles will be hitting the market, and not all of them will be marked as flooded.

Stephen Fogel

About the Author

Stephen has been an automotive enthusiast since childhood, owning some of his vehicles for as long as 40 years, and has raced open-wheel formula cars. He follows and writes about the global automotive industry, with an eye on the latest vehicle technologies.

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