Rust Busting

If you live north of the Mason-Dixon line and east of the Plains, brace yourself.

The 2002 Farmer's Almanac suggests this winter portends conditions that are ripe for recalls. Expect “another very active winter weather pattern,” says the storied book. “We predict a few heavy snowstorms and even a near-blizzard (in the second week of February).”

Stir in several million tons of road salt, serve on sheet metal at just above freezing and you have a recipe for repair nightmare — a regular feature on last year's menu for National Highway Traffic Safety Admin. investigators. The agency's final safety recall report for 2000 cites salt in five actions affecting more than 2.2 million light vehicles:

Auto makers fairly point out these recalls target only those vehicles in states where salt is widely used to de-ice roads. But the threat isn't going to go away soon.

Forget the fact that salt comes cheaper in these areas than other remedies such as volcanic ash. Its offending chloride ion is so insidious that the delivery system has also become contaminated. Need convincing? Road commissions across the country report they are experimenting with GPS systems to deploy salt trucks more effectively.

If you're an engineer, however, you don't take this news with a grain of salt.

“There's two things you can do with corrosion,” says Kathy Minnich, manager of materials engineering and testing at Ford Motor Co. “You can either keep it dry, or you can provide a barrier between the environment and the part you're trying to protect.”

The first remedy requires perfect execution, she warns. The second demands informed decisions on material selection.

And in keeping with an industry climate that calls for more accountability and input from suppliers, Ford is working with its Tier 1 network to promote deeper understanding of the problem. Traditionally, suppliers have viewed their components in isolation.

“They don't really throw the corrosion in while they're doing their functional durability evaluation,” Minnich claims.

But salt isn't the lone villain behind corrosion, she adds.

“Corrosion's essentially an electrical process. And you need something to carry the charge. And that's what the moisture does for you. It provides a medium for this charge to flow.”

As a backup plan, Ford monitors product performance in a ready-made laboratory. It's called Nova Scotia.

The province on Canada's east coast not only has nasty, wet winters, it's under constant assault by sea spray, Minnich says.

If there is a harsher environment, she adds, it's the dank hold of an ocean-going cargo ship. But — with some difficulty — Ford found a solution for its affected overseas markets.

Corrosion-susceptible areas of every exported Cougar, Taurus, Explorer and Windstar get a pricey wax job to keep the vehicles showroom fresh. (Ford won't say how much it pays per unit, only that doing the same for domestic vehicles would be cost-prohibitive.)

The trick was finding the right agent, says Minnich. “The last thing we want to do is spray it on a rubber boot and the next thing you know, the thing swells up and leaks and you've got another problem,” she adds.

(Note to those who live between the Rockies and the Great Lakes: The Farmer's Almanac says your winter will be a breeze. After all, it's a dry cold.)