A record number of cars were affected by hurricanes and storms in 2005. Hurrican Katrina alone may have damaged as many as 400,000 cars, according to the National Automobile Dealers Association. Unfortunately, many of these damaged vehicles may be fiding their way to a used-car lot near you. That means that many car buyers may unknowingly buy a vehicle that has hidden water-related problems. Flood damage may be hard to spot, but it can permeate the vehicle and cause ongoing problems for the rest of the car's service life. Flood damage can ruin electronics, contaminate lubricants, and threaten mechanical systems, often without leaving outward signs. It can take months for incipient corrosion to find its way to the car's computer systems or air-bag controllers.

Mold and mildew is another major problem. Even after soggy seats and carpets dry out, the lingering smell may never go away completely.

Most flood-damaged vehicles will be written off by insurance companies. Once it's declared a total loss, a car is supposed to get a new title, called a salvage title. Such titles, depending on the state, are usually either plainly marked or "branded" with the word "salvage" or "flood," or obscurely marked, with a coded letter or number. They are then typically sold at a "salvage" auction to junkyards and vehicle rebuilders, who may resell them. This practice is legal, as long as the flood damage is disclosed to buyers on the title, say experts at Carfax.com, a Web site that tracks vehicle histories and sells reports to consumers online.

But some flood-damaged vehicles will make their way back onto the used-car market, rebuilt and disguised as ordinary used cars with clean titles. In addition, local mechanics who buy vehicles privately and resell them might not generate a paper trail indicating that a vehicle has been flooded. Some cars may not even have a title, so be wary.

Reports are available online at www.carfax.com or from Experian at www.autocheck.com for about $20 each (unlimited reports are $25). Such vehicle-history reports can alert you to some types of problems, but they are no guarantee that a vehicle has no hidden problems. That's why it is important to get any used car inspected by a trusted independent mechanic before you buy it.


HOW TO SPOT A FLOOD-DAMAGED CAR

Here are some quick checks that you can perform yourself:

• Look under the carpets to see if they are wet, damp, or muddy.
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• Check the seat-mounting screws to see if there is any evidence that they have been removed. To dry the carpets, the seats must be removed--not generally a part of normal maintenance.
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• Inspect the lights. Lights are expensive to replace, and a water line may still show on the lens or the reflector.
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• Inspect the car in difficult-to-clean places, such as the gaps between panels in the trunk and under the hood. Water-borne mud and debris may still cling in these places.
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• Look for mud or debris on the bottom edges of brackets or panels where it couldn't naturally settle from the air.
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• Look at the heads of any unpainted, exposed screws under the dashboard. Any unpainted metal in cars flooded in New Orleans will probably already show signs of rust.
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• Check the rubber drain plugs under the car and on the bottoms of doors. If they look as if they have been removed recently, it might have been done to drain floodwater.
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• If you need to dig deeper, remove a door panel to see if there is a water mark on the inside of it. If you are from an area impacted by a flood and have a car that was not damaged, be aware that buyers may still suspect that it was. Consider having a mechanic inspect the car before you sell it so that you can present potential buyers with a clean bill of health.