driving in flood water

Can Cars Drive Through Water?

Unless we are talking about heavy-duty and extensively modified off-road vehicles, it is safe to say that cars and water don’t mix well. There are various mechanical and electrical components not likely to cope well with anything more than a few splashes. Still, that doesn’t mean that puddles on the road are the only thing your car can handle. Whether out of necessity or just for the fun, you may find yourself in a situation where you need to cross small pools of water or even worse, floodwater in your car. To some, this may seem like a benign adventure, while others may see it as an impossible task. No matter the reason, there are several rules to follow if you want to avoid getting yourself, your passengers and your vehicle in danger.

What Do You Do If You Drive Through Water?

The first thing to consider is the car itself, as they are not all designed in the same way. Most importantly, you need to know what is a wading depth of your car. This shows the water depth through which your car can go through. You can find this information in your owner’s manual or on various places online, at least if you own are four by four vehicle or an SUV. Things might be a little more complicated if you have a family car or a minivan, as usually there is no such information for cars like that. As a rule of thumb, never go through water that is deeper than a center of your wheels. On most cars, this will be a foot or a foot and a half.

driving in a flood

Next, pay attention to the air intake location. In most cases, it will be behind the grille and leveled with headlights. An air intake that sits low to the ground may let the water into the engine, causing major damage. Last, make sure that all electrical components and harnesses will not be submerged.

The water you are about to drive through is another variable you must take into account. This might be a small stream in the countryside on your way to the campsite. Or the heavy downpour, combined with clogged storm drains, that has covered a part of your street with feet-deep water. The most important is the depth, as going even a short drive through water that is too deep may cause stalling and even irreversible damage to your car. Next, you must see the surface below the water. A large rock on the stream bed or a manhole with missing cover can damage the wheel or suspension of your car or even make it stuck. Last, avoid crossing fast water streams, such as mountain creeks, as a situation within them can change within seconds. If any of these conditions are not met, turn around and find another way.

car in water

Once you’ve decided to go through the water, follow these simple guidelines. Before you get in, roll the windows down, just in case. When it comes to forwarding water, slow and steady wins the race. Do your best to maintain momentum and a steady pace, don’t change direction or gears and no matter what happens, don’t stop. Try to create a bow wave in front of your car, as this will prevent water from entering the engine bay. Once you’ve made it across, stop so the water can drain from your car. Let the engine running and depress the brakes a few times. Also, check under the car and inside the engine bay for any potential issues caused by water.

How Do You Drive In Flood Water?

flood water driving

Although the flood might seem like a perfect opportunity for putting your water-tackling abilities to good use, it is not as simple as that. In fact, it can be very dangerous. In most cases, floodwaters are fast, violent, and very muddy. This makes assessing how deep the water is and what’s the surface beneath like impossible. Floodwaters can carry rocks, bricks, and other debris, turning a once smooth road into an obstacle course. In such conditions, it is easy to get stuck or stranded. If that happens, abandoning your car is not a safe option, as you will find yourself standing in strong and dangerous water. All of this makes driving through flood water extremely dangerous, so avoid it at all costs.

How Do I Know If My Engine Is Flooded With Water?

If your car has been partially flooded or had stalled while driving through floodwater, there are several things to check before you can safely try to restart it. The biggest danger in this situation is the possibility that the water has entered the engine itself. As you may know, water cannot be compressed. So, if it gets inside the cylinder and fills it up, something must break when the engine tries to compress it. Usually, this will be a connecting rod, causing a strong knocking sound. To prevent eventual engine damage, before starting a car that might have been underwater, remove the spark plugs and crank the engine. This will expel any water that might be within cylinders.

pickup in flood water

Other water-related engine issues include stalling, sputtering, and sluggish acceleration. This happens because moisture can upset the engine’s electrical system. If the water gets in spark plug holes, it will cause a random misfire. And if it gets inside electrical connectors, it will cause various false readings. Check all electrical parts and connectors that have been in contact with water and dry them out if necessary.

Lastly, the transmission in any car has a breather at the top of their casings. If the water is deep enough, it can get inside your gearbox or axle, where it dilutes the oil. However, this is something that can easily go unnoticed, as there will be no immediate symptoms. With time, the water will cause corrosion on internal transmission parts, and reduced lubrication will cause excessive wear. By the time you notice something is wrong, the damage to the transmission will be extensive.

In any case, make sure to always keep a car emergency kit inside your vehicle. If for some reason your car was to stall when crossing flood water, an emergency kit will ensure you stay warm and safe while you wait for help.

About Bojan P

My name is Bojan - I am a car enthusiast, specialised in the vehicle diagnosis, repair and maintenance with 10 years of practical, hands-on experience. In addition, I have a Masters degree in mechanical engineering.

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