What to do if your vehicle has been flooded

Owners of cars submerged in floodwaters are warned not to try starting them.

RACQ Principal Technical Researcher Andrew Kirk said starting the car could cause more damage to the engine and, for EV owners, was dangerous.

“If the engine is started, water can get pulled in from the intake manifold, air cleaner and intake,” Mr Kirk said.

“If the engine is running and this occurs, the engine will hydraulic lock because you can’t compress water like air and fuel.

“This will very likely cause internal damage such as bent conrods and valves.”

Mr Kirk said it was crucial owners of flooded electric and hybrid vehicles did not start them as there was the possibility of electrocution or fire from short circuits.

“Vehicles with high-voltage batteries should only be towed to an authorised repairer and inspected,” Mr Kirk said.

“The tow-truck operator also needs to be aware that the vehicle has a high-voltage battery and that it has been flooded.”

Mr Kirk said if water entered the engine of a petrol or diesel vehicle, rust would be an issue for moving components such as crank and camshafts, bearings, timing chains, rings and cylinder bores.

“Whilst most of the rust will wear off once the oil is changed and the engine started, it will vastly accelerate wear to the moving components,” he said.

“There could also be mud and debris in the intake. The engine should be dismantled and inspected.

“For the uninsured, this will be expensive.

“This will be similar for the transmission and driveline, although water ingress is less likely if the vehicle was parked and not being driven.”

Mr Kirk said water could also contaminate fuel and oil, and enter internal components.

“For the electrics, even if everything is pulled out of the interior and dried, there could still be ongoing electrical issues due to corrosion forming in wiring plugs and connectors,” he said.

“It would be a massive and expensive job to go through every single connector, as there would be thousands, and dry, clean and lubricate them.

“There is also the health issue. The interior carpets, carpet lining, roof lining, seats and fabrics will all be subject to mould and contaminants and must be treated and disinfected.

“All this work will be expensive and ongoing issues are highly likely, which is why insurance will simply write off a flooded vehicle.”

He said owners of uninsured vehicles should contact their mechanic.

RACQ members can lodge their insurance claim online or by calling 13 72 02.