The goal is to ensure that the water does not reach the upper parts of the engine bay where the car electrics are found. PHOTO/EDGAR R. BATTE
Did you know that just 15 centimetres of flood water can float your car? Experts warn that in some cases, 10 centimetres of water should be a cause for alarm to drivers of small cars. This means that Sport Utility Vehicles (SUVs) such as Toyota Prado and Range Rovers are less likely to encounter problems until the water reaches about 45 centimetres.
Automotive mechanic and car expert Paul Duke Kaganzi says, “Driving in shallow flood waters can be hazardous, depending on the force of the flood waters. It may be an exaggeration to claim that 10 or 15cm of flood water will make a small car such as the Vitz float.”
He adds that technically, a Vitz with a ground clearance of 15.5 to 17cm, depending on tyre sizes, will float in a water depth of 60cm. A study by an Australian university concluded that a small car with a ground clearance of less than 15.5cm may be moved by flood waters of 15cm depth if the water speed is 12.6 kph or three to four meters per second.
However, it takes 60cm depth to float a small car, while it takes 95cm water depth to float a bigger SUV. This clarification of the “15cm to float” claim does not negate the danger posed by shallow floods to the lives of the car occupants and the risk of severe damage to the engine if it ingests water through the air intake system.
It is often difficult to accurately gauge the depth of the water with just a glance, but understanding that even a small amount of water can cause major damage is important. Most of us will find ourselves having to drive through floodwater now and then, especially when living in areas prone to flooding.
According to theconversation.com, other than driving slowly, here are some things to be aware of while driving through a flooded road:
Flood waters are rarely clear but muddy and opaque, which makes it impossible to see where the road begins and ends. It also makes it hard to see obstacles that may lie hidden in the water.
When roads flood, maintenance hole covers can get lifted and moved by the water, leaving large gaping holes. Being aware of this could be the difference between being stuck or making it safely to your destination.
Unpredictability
While you can judge rightly that the water is shallow enough for your car to pass, flood water levels can change abruptly. You may enter the flood when the water is 10 centimetres and by the time you come out from the other side, it is 20 centimetres deep. Knowing this will help you determine whether you should proceed or park and wait.
How to drive through floodwater
If you ever find yourself forced to drive through a flooded section of the road, try to keep on the side of the road that is on higher ground to ensure that the car keeps on the side of the road with minimal water. The goal is to ensure that the water does not reach the upper parts of the engine bay where the car electrics are found.
Water plays havoc with vehicle electrics and could cause several issues, including damaging the engine. The best option is always to stop and wait for the water to go down but if this is out of the question, then be sure to follow these tips:
Do not stop
Before starting to cross the flooded section, make sure there will be no foreseeable obstacle to cause you to stop in the middle of the water, which may cause your engine to stall. When this happens, water will enter the engine via the air intake system, causing major damage.
Beware of fast-moving water
There is a difference between a standing flood and a fast-moving ‘rainwater river’. A stagnant flood is a lot safer than a moving flood. If the water is moving, chances are your car will float and get swept away. Park and wait until the water subsides.
Drive slowly
You may be tempted to drive fast through a flooded section so that you get done with it and go your way but do not take the bait. Driving too fast through water may cause aquaplaning, a situation where car tyres lose their contact with the road and slide on a layer of water between the road and the tyres. Drive slowly and steadily (around 3-4 mph) so you do not make a bow wave that may cause water to enter the engine through the air inlet.
High revs
Do you know that gear 2 is in your automatic transmission car? This is where it applies. It gives you high revs but at low speed, which is ideal for flood driving. High revs help the car to blow strongly through the exhaust pipe, keeping water from entering the engine through the tail pipe.
DAMAGE
Other than engine damage, here are the different ways floods may damage your car:
Brake damage: Becausebrakes get very hot during driving, they can getdamaged after you pass through a flooded spot because of the abrupt temperature change. The brake disk may warp due to the instant temperature change, from hot to cold, resulting in vibrations and unpleasant sounds when you apply the brakes.
Transmission damage: If water enters the clutch box during the time you drive through the floods, it will cause damage to components. This is because water can dissolve the linings on the clutch plates, causing them to slip and fail.
Electrical issues: Over the last 30 years, cars have slowly become electrified. Things such as brakes, electrical control unit headlights, brake lights, indicators, central locking system, AC, and windshield wipers, among others, are all controlled by electricity. Cars come with advanced sensors and computer systems that can get damaged by driving through water.
Interior water damage: This can happen when the car is submerged in the water and the water finds its way into the cabin. Once the water enters the interior, the seats, the floor and the dashboard get soaked and are at risk of damage from mould and mildew if care is not taken to dry them immediately
