August 06, 2015
Nathan Bomey

Ford engineers have morphed into exterminators — and for good reason.

A common form of spider, it turns out, likes to nest under the hood in vehicles. That sounds harmless enough, but it can cause big problems, including possible fuel tank cracks that can ignite vehicle fires.

"We’re always working to improve and adapt to whatever the environment or the regulatory regime throws at us," Ford fuel systems engineer David Gimby said.

Ford (F) has a solution: a new cylindrical "spider screen," which is being installed on all Ford vehicles globally starting with the 2016 Focus RS.

The eight-legged offender in this case, often referred to as a yellow sac spider, is already believed to be responsible for more bites to humans than any other spider, according to Michigan State University researchers.

Apparently it takes pleasure in wreaking havoc on cars, too. Ford found that the yellow sac spider seeks out cavities to build cocoons for laying eggs or taking shelter. In vehicles, that often leads it directly to a fuel vapor line.

When the arachnid spins a web, it can cause blockages that disrupt fuel vapor and then generate engine damage. A strand of a yellow sac spider web is as strong as an equally thick strand of steel, according to Ford.

Darrell Ubick, a spider specialist at the California Academy of Sciences, said the yellow sac spider is "very common" in houses.

"Their presence in the car is surprising, but not unexpected as the car engine area attracts many organisms, such as mice," he said in an email. "I’ve heard of spiders causing similar problems in farm equipment by making their retreats in tubular cavities."

It's a particularly virulent issue for some automakers. In March 2014, for example, Mazda recalled 42,000 Mazda6 vehicles from the 2010-12 model years after discovering that spiders could weave webs in a canister vent hose, causing an "excessive amount of negative pressure" in a fuel tank, according to a document filed with the National Highway Traffic Safety Administration.

USA Today