And when water gets inside the engine, problems get even worse. Affected parts will usually need replacing to guarantee they'll be as trouble-free as before the soaking. And it's the cost of this which leads to most flood damaged cars being written off.
Obviously, the damage caused depends on how high the flood waters were. Up to the axles and you'll need to get a mechanic to inspect the brakes and wheel bearings; if it reaches the windows the entire engine compartment and interior will have been affected making it far more likely to be a write off.
It's not just the water you need to beware of either. Floods mean drains back up and sewage works are breached, mixing all kind of horrific contaminants in the water – and this will need professional cleaning. If the water is salty, corrosion will be rife when the car dries out. It's vital you get a professional to inspect your vehicle after a flood, as many of the problems will be hidden from view.
How to spot a flooded motor:
Even to the trained eye, a flooded car can be hard to spot. However, experts from the recovery organisations gave us some tips on what to look out for.
Rust: Look for corrosion on screw heads and fixings in areas that would otherwise be sheltered from the elements. Rust inside the car is a tell-tale sign of flood damage.
Sniff test: If there's a strange smell from the interior, fabrics might have been soaked with filthy water. This pong is incredibly hard to shift and will linger.
Steamy windows: If the car has a tendency to steam up easily, it might be due to condensation from flooding. However, this is only likely on a car recently flooded, not one damaged a few years back.
Warp speed: Look for ill-fitting or distorted interior panels that may suggest removal for drying. It's the same for carpets.
Dirty job: Look for silt or fine sand in areas not readily accessible that may have been brought in by flood water. Look below the dash panel and in small crevices.
Light saver: Warning lights on the dash could point to electric gremlins as a result of water damage. These are likely to be very expensive to fix.
How to drive through a flood:
Make sure you know how deep the water is and how fast it is flowing – never enter water you don't know the depth of! It's a good idea not to follow the car in front through a flooded road – its bow wave will only make things worse. Instead wait for the water to settle and drive slowly at the highest part of the road (usually the centre).
Select a low gear and keep the revs high to stop water entering the exhaust and then test your brakes once you're out. Make sure you know where the air intake is on your car too - sometimes they are lower to suck up cooler, dense air but this makes them more susceptible to water ingress.