Year by year, the dry months are brought to an abrupt end with the first downpours that mark the rainy season. The highs of the past summer may be difficult to shake off, but the floods the rains bring are not challenges to take lightly.
Heavy rains can quickly overwhelm the drainage systems of many streets, causing waters to rise with just the briefest of torrents. Past events, like Ondoy, have shown that even streets that typically stay flood free can quickly be submerged with the right conditions. As such, sometimes, the best way to get to where we need to go may be to drive through a flood.
Before biting the bullet and driving straight through it, there are a few things to keep in mind first.
Assess your vehicle
Crossing water exposes your vehicle and its engine and electronic components to possible damage. Engines are tightly sealed, but other parts of the car are not. Getting water into a vehicle’s intake manifold, the ECU, or other hydraulic pumps and compressors may cause it to stall right in the middle of a flood. Take note that any damage that may result from crossing flood waters are difficult to repair, equating to weeks in the shop, and a case that’s even harder to justify with many insurance companies.
If you must drive through flood waters in your family sedan, hatchback, wagon, or van; stop and observe others crossing first. If water appears to be deeper than your tire (1 ½ feet, 400 mm; Note that this limit may vary with each vehicle), don’t cross as this will only result in your vehicle stalling. A good rule of thumb to observe is the above the tire rule. Critical engine components like the intake manifold, ECU and fusebox are typically mounted just above the tire. If the flood water exceeds this, it is likely to enter your intake manifold, or short the ECU or fusebox and cause bigger problems.
For floods that appear taller than 400 mm, before crossing, be sure you’re in a vehicle that has been designed to drive through some variety of challenging terrain. Vehicles like crossover SUVs, pickup-based SUVs, and pickup trucks have been designed from the ground up to tackle difficult terrain, be it sand, mud, rocks, off-road trails or floods. As such, engineers have fitted various measures to protect the vehicle from damage that may result from this; from front skid plates to divert water away and protect the radiator from rocks, to tighter seals around hoses and ECU housing.
What strengths matter
Some may say that it’s safe cross floods so long as you’re in a tall vehicle. Indeed, tall vehicles have an advantage, but it’s not a hard fast rule for all. Just because a vehicle appears tall, it’s no guarantee. Vans and MPVs, for example, may appear to be tall vehicles, but because their engines are typically mounted low (under the driver’s seat) they may not necessarily fare better than your average sedan or hatchback.
Some say ground clearance is the most vital figure to look at, yet this is no guarantee either. Engines come in a wide variety of configurations, and while they may boast of really high ground clearance, may be fitted low in a vehicle’s chassis, putting it at greater risk for damage. Cab-over-engine trucks, for example, boast of high ground clearance, but because their engines are mounted low in the body (under the seats), may not cope too well with a flood.
Perhaps the most reliable figure to look for is water wading depth. Many astute car shoppers will note that not all cars advertise this figure. This is because this is only measured for vehicles specifically designed to go through floods and deep water. Wading depth is the maximum height of water above ground that the vehicle is rated to drive -or wade- through.
More rugged vehicles like 4x4 pickups and SUVs will typically have this figure in their brochure. The Ford Everest, for example, has a water wading depth of 800 mm (2.6 feet). Take note that this vehicle varies with each make and model, and it’s best to consult your manual or dealer. If the numbers seem a bit abstract, take a measuring tape and measure how far up against your body, or even better, a car’s body that figure goes to see how high up it is. In the real world, this means it can tackle flood waters that go just above its front bumper. This technique will help you determine, in the real world, how deep flood water is just by observing the cars crossing it.
How to get through a flood
Now that you’ve determined if your car can drive through a given flood or not, there are some pointers to keep in mind when actually driving through it.
Before anything else, approach the water slowly. Avoid crossing when there is oncoming traffic, particularly a large vehicle, as it could generate a bow wave that would be dangerous for your car.
Once clear, choose a low gear or drive mode, to allow the car to power through the extra resistance flood water can create (i.e. first or second gear in a manual or S or L in an automatic). If you’re in a Ford Everest 4x4, simply put it to D and set the Terrain Management to Auto. The Everest is set to all-wheel drive by default, guaranteeing constant traction all the time.
Apply constant pressure on the throttle and drive at a slow and steady speed. Find the highest point of the road and cross as close to it as possible at about 5-10 km/h. Avoid slowing down, stopping, or changing gear. Staying in the same gear and applying constant throttle pressure ensures a steady stream of exhaust coming out the tailpipe, preventing water from entering the engine.
Never overtake the bow wave. As you cross, flood waters will form a bow wave around your vehicle’s front bumper. Like any wave, this also means that the water behind it is lower than the normal level, keeping your vital engine components dry.
If you’ve managed to successfully cross the flood with little incident, don’t speed off right away. Continue driving at the same speed and pay attention to any change in the vehicle’s normal “feel” as these may indicate any issues caused by the flood.
If something feels different, find a clear area far away from the flood, pull over, turn off the engine and try to examine what could be causing it. Check your engine bay for any potential damage or debris that could have been trapped inside. Peek under the car too for any plastic bags, twigs or leaves that could have lodged in the axles.
Tap the brakes once or twice to make sure you have the full brake pressure. If it feels weaker than normal or pulls to one side, apply constant but light pressure while driving slowly to help heat up and dry out the brake discs and drums.
Even if everything feels fine, make sure to schedule a vehicle checkup within the week just to spot any problems you may have missed.
Driving through the floods should not be a roll of the dice to see if you make it through or stall right in it. Armed with some knowledge of your vehicle, how to spot and assess conditions, and the proper driving technique, your drive should be a far less worrying affair, and help you make it to your destination with no problems.