How badly does flooding damage a car?

Flood-damaged car

This might look like a watery write-off but it could be dried out and sold on

Green Flag head of rescue and motor claims response, Neil Wilson, believes one in seven cars rescued by the company in parts of the country hit by flooding will be an insurance write-off. That means six out of seven cars from flooded areas – thousands – will be put back on the road. And some will undoubtedly be sold as used cars. Here are some simple checks to ensure you don’t buy a flood-damaged car.

How badly do mechanical parts suffer?

Nick Reid, technical expert and head of transformation at Green Flag explained: “Being submerged can have a catastrophic effect on various mechanical components as water penetrates and sets off the corrosive process. It can shorten the life of the exhaust and catalytic converter. And it can have a detrimental effect on wheel bearings, brakes, and engine parts such as the alternator and starter motor.”

What about water and electronics?

Nick said: “Under the carpets of modern motor vehicles and in the footwells are some very complicated electronic control units. One of the most significant is the airbag control system and its wiring. Water penetrating this could cause a malfunction, potentially detonating an airbag while you’re driving.”

How does flooding damage an engine?

“Flood water can destroy an engine,” Nick revealed. “An engine works by drawing fuel and air into each cylinder, compressing the mix and then igniting them to release power. The key word here is ‘compressing’. If a vehicle has been submerged the cylinders will almost certainly be full of water. This doesn’t compress. The result is what’s known as ‘hydraulic lock’. Trying to start the engine will at best blow the starter motor, at worst inflict serious mechanical damage.”

How do you tell if an engine has been flooded with water?

Nick explained: “Lift the oil filler cap. If there’s a white mayonnaise-like substance on it, water has got in and mixed with the oil, which you definitely don’t want. It’s so serious that some flood-damaged cars will have had their engines replaced. Check this by looking for the engine number on the engine itself. Then make sure it tallies with the one on the V5C.”

Is the car’s price right?

A flood-damaged car really could be more trouble than it’s worth. And although it may not have any significant damage that’s immediately apparent, the flooding could have shortened the life of expensive components. Check what the car should be worth by entering its registration number on the CAP Automotive valuation tool. If it’s being sold for significantly less than that, it could be to secure a quick sale following flood damage.

See how to avoid flooding a car

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