Four things to do if your car gets caught in floodwater
Modern cars are packed with electronics, sensors and control units, while hybrids and electric vehicles are even more complex. When your car gets caught in floodwater, one wrong move can cause the real damage. Here’s what to do and what to avoid
Heavy monsoon showers have once again brought parts of Dhaka and other cities to a standstill, with roads turning into temporary canals and vehicles left partially or fully submerged. While some cars remain stranded after attempting to cross flooded roads, others suffer damage simply from being parked in water for several hours.
Many drivers instinctively try restarting the engine or driving away as soon as the water level drops. Unfortunately, that can be the costliest mistake of all. Modern cars are packed with electronics, sensors and control units, while hybrids and electric vehicles introduce another layer of complexity.
Here are four things every driver should know.
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1. Never restart a stalled engine
If your car stalls while driving through floodwater, do not try to restart it.
There's a good chance water has entered the engine through the air intake. Cranking the engine can cause hydrolock, where water inside the cylinders prevents the pistons from completing their stroke. The result can be bent connecting rods, damaged pistons or even a destroyed engine.
Instead, switch on the hazard lights if possible, move yourself and your passengers to safety, and arrange for the vehicle to be towed to a workshop. Even if the engine didn't ingest water, it is far safer to have it inspected before attempting to start it again.
Similarly, if a parked vehicle has been submerged high enough for water to enter the engine bay, avoid starting it until it has been checked.
2. Avoid driving into deep water
Many flooded roads appear harmless but hide deep potholes, open drains or uneven surfaces beneath the water.
As a rule of thumb, avoid entering water that reaches above the bottom of the doors or the centre of the wheels. Even if your SUV has higher ground clearance, that does not mean it is waterproof. Water entering the air intake is enough to destroy an engine regardless of the vehicle's size.
If another vehicle has stalled ahead, treat that as a warning rather than assuming yours will make it through.
When there is no alternative but to cross shallow water, drive slowly and steadily in one gear without sudden acceleration. Creating a bow wave or stopping midway increases the risk of water entering the engine.
3. Dry the cabin quickly
Floodwater rarely consists of clean rainwater. It often contains mud, sewage, oil and other contaminants that can cause corrosion and mould.
If the interior has been flooded, remove the floor mats immediately and allow the cabin to dry completely. Carpets, seat foam and insulation can trap moisture for days, leading to unpleasant odours and corrosion beneath the floor where important wiring harnesses are located.
The sooner the cabin is cleaned and dried, the lower the chance of long-term electrical issues.
Drivers should also inspect the boot, spare wheel compartment and under-seat areas, as these often retain water long after the rest of the cabin appears dry.
4. Inspect before driving again
Even if the engine starts and appears to run normally, floodwater may have contaminated vital components.
Engine oil, transmission oil and differential oil should be inspected for signs of water contamination. A soaked air filter is another indication that water may have entered the intake system.
After driving through water, brakes may feel less effective until they dry. Gentle braking at low speeds can help restore normal performance, but any unusual vibration, warning lights or noises should be checked immediately.
Avoid assuming everything is fine simply because the car still moves. Electrical faults caused by water can appear days or even weeks later.
