The southern United States just got battered by two of the biggest hurricanes ever, and Puerto Rico got hit even harder. Once the waters start to subside, and the power is back on, the next order of business for a lot of people (if their house is okay) is going to be their cars. The bad news is that 21st Century cars have more electronics in them than a smartphone, and are less water resistant. However, just because it got water nearly up to the windows doesn’t mean your car is junk.
But for the amount of effort involved, and the chance of electrical gremlins, odors, and mold, if you have comprehensive coverage, take the payoff from your insurance company. The only time repairing a flood-damaged car is really worth it is if 1) the damage is minor, or 2) it is an older model with sentimental value. Cars that have been flooded with saltwater or underwater for days should be considered unfixable.
Drivetrain
The very first thing to determine with any flood-damaged car is how badly contaminated is everything in the drivetrain. Start with the motor and drain the oil to get some idea of how much water got in. Next, pull the spark plugs, squirt fresh oil into the cylinders and crank it over by hand to pump out the water that got into the intake. Open the airbox and throw away the waterlogged air filter; air won’t flow through it.
No matter if you have an automatic transmission or a stick shift, you’ll need to drain the fluid. Continue the process and drain the other fluids from the power steering pump, rear differential, transfer case, etc. Sitting for a few days with an oily water mixture won’t destroy these components, but dirt and sand can if you don’t get it all out.
Finally, you’ll need to drain the fuel tank to get out any water that made its way in there. Water doesn’t burn and will corrode fuel lines from the inside out, so you may have to dispose of a whole tank of gas.
Once empty, put a few gallons of new, fresh, clean gas in the tank and cross your fingers. Refill everything with the proper oil, but don’t put the spark plugs back in just yet.
Electrical
The biggest hurdle of repairing a car that has been through a flood is going to be the state of its electrical system. Much of the wiring and charging system in your car is made to be somewhat weatherproof, which is how you can drive it in the rain. But the computer, sensors, and wiring harness inside the car were never made to be submerged.
Disconnect that battery and open the doors, hood, and trunk. Once you have changed the oil and other fluids, let the car sit in the sun all opened like this to dry for at least a day.
Now, it is time for the moment of truth.
Reconnect the battery (or replace it if bad) and turn the key to “on”. If you are lucky, the dashboard will light up normally.
Turn the key and see if the motor cranks. If it does, you can replace the spark plugs and try to start it.
Even if the motor starts and runs normally, you are still only halfway home.
The Interior
The interior of the car is one of the toughest parts to bring back after a flood, even if the water wasn’t too deep. Most automotive carpet still has some jute backing to it, and all seats are made of foam rubber, both of which soak up dirty water like a sponge.
No matter what, you are going to have to tear out the carpet and padding, and replace it. Luckily that part is not hard, and rarely more than a couple hundred dollars.
You are also going to have to peel the upholstery off of the seats in order to dry the seat foam. Cloth seat covers may be able to be washed and reused, vinyl is pretty weatherproof, but if you had leather, it is ruined. Getting new foam and upholstery is likely to cost you several thousand dollars.
Many door panels are backed with cardboard, so take them off to dry in the sun. Car doors have a drain in the bottom, and a vapor barrier to keep the inside dry, but that work against you in the event of a flood. You will need to peel back the plastic under the door panel as well.
The Aftermath
If you have gotten the motor running, the computer and dash seem okay, and the interior is clean and dry, you still aren’t out of the woods. The whole brake system will have to be gone through, with new fluid, pads, and shoes just to be safe. Then you can drive it and wait for the inevitable issues to crop up.
Just like a phone dropped in a toilet, the weird electrical issues with a flooded car may not appear for days or weeks. Pay attention to strange noises and odors. Keep a close watch on the dashboard for random warning lights. Look for fog to appear in both exterior and interior lights, including the instrument cluster.
Bringing a flood-damaged car back to life is rarely worth it, but an estimated half million cars were flood damaged in Texas alone this year, and more than 25% of them aren’t covered by comprehensive insurance. That means thousands of people are going to be stuck with flooded cars and no insurance money.
Looking at a used car? Carfax will check the VIN number for reports of flood damage for free and has an online flood damage spotters guide.