It’s the stuff of nightmares: You’re driving through a puddle that turns out to be much deeper than you thought. Before you know it, you find yourself running the risk of a flooded engine. Whether you’re caught by surprise in a sudden rainstorm that turns the street into a swimming pool or come across a washed-out section of road with a creek flowing across it, it’s never a good idea to expose your car to deep water.
If you find yourself past the point of no return, don’t panic. There are a few things you can do to avoid a flooded engine. The first, and most obvious, is to shut off the ignition, but only if it is absolutely safe to do so. If, for instance, you find yourself in the middle of a deep parking lot puddle, you can switch the car off immediately and call a tow truck or push the vehicle out manually, if you’re particularly brave.
If, on the other hand, you happen to be driving through water with a strong current on a roadway, it’s safer for you to forget about potential engine damage, put the car in reverse and attempt to back out of harm’s way immediately. All it takes is 12 inches of moving water to push your vehicle off the road.
Regardless of whether you decide to back up or keep pushing forward, make sure you do so at a slow, steady speed. Driving quickly through standing water is a great way to generate a wave of liquid under your car that can enter into your engine bay and wreak havoc.
Determine If Water Entered Your Engine
The most common way water damages a car’s engine is when it gets sucked up through the air intake. When too much water is introduced into your motor’s cylinders it results in hydrostatic lock, or “hydrolock,” an engine state in which the pistons freeze and the engine stalls. This sudden stoppage can irreversibly damage internal components and turn your car’s motor into little more than a glorified paperweight.
Although it takes a fair amount of water to cause hydrolock, remember that even small amounts of moisture inside your motor can cause it to stall. The easiest way to quickly decide whether your engine sucked in any water or not is to locate the car’s air intake once you’ve reached safety. If there’s noticeable moisture high up in the engine bay, above the depth of the water, then you likely have nothing to worry about; if there’s evidence of moisture penetration down low, such as beneath or near the bumper, then you have cause for concern, especially if your vehicle was submerged significantly at any point.
Take It to a Mechanic
Even if your engine is still running after your watery encounter, if you suspect that your intake might have sucked in any water, it’s a good idea to get things checked out by your local NAPA AutoCare Center. In doing so, you can also determine if any of your car’s electrical components, such as bulbs, wiring or sensors, need to be replaced after being waterlogged.
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Having been bitten by the car bug at a young age, I spent my formative years surrounded by Studebakers at car shows across Quebec and the northeastern United States. Over ten years of racing, restoring, and obsessing over automobiles lead me to balance science writing and automotive journalism full time. I currently contribute as an editor to several online and print automotive publications, and I also write and consult for the pharmaceutical and medical device industry.