Shortly after the dawn of new millennium, automakers started implementing bio-plastics made from corn starch, genetically engineered bacteria, or vegetable fats and oils. The rationale for this was that sustainably sourced materials were better for the environment and lowered dependency on petrochemicals. Unsurprisingly, bio-plastics gained in popularity at roughly the same time as ethanol.
Since at least 2010, soy-based bio-plastics have been a popular alternative for wiring insulation in automobiles. But there’s a problem — rodents love how it tastes. This has allegedly resulted in a surprisingly high number of owners reporting that rats chewed through the wiring inside their automobile.
While the problem isn’t entirely new, the frequency of the incidents appears to have been spurred by automakers using more palatable materials. In fact, the issue has grown so bad in recent years, numerous lawsuits have cropped up demanding manufacturers pay for damages. Honda was named in a suit from two years ago involving 2012 to 2015 model year vehicles, and Toyota was hit with one for cars produced between 2012 to 2016.
Bio-plastics were in widespread use at this point. Both Kia and Hyundai were named in subsequent rodent-related lawsuits, and practically every major manufacturer uses plant-based plastics on at least a few models built within the last decade. It sounds benign but, considering that rats eating your car typically isn’t covered under a vehicle’s warranty, owners have to shell out hundreds if their insurer isn’t interested.
According to the Detroit Free Press, the growing rat problem isn’t the result of paranoia, either. John Pappas, owner of Main & Hudson Service in Royal Oak, Michigan, claims he sees at least one vehicle every month with gnawed-on wires. “They’re going environmental on the wires,” he said. “There’s good and bad in everything. It is a common issue.”
Jim Stevens, a sales representative at Suburban Ford of Ferndale, stated finding rats chewing through wires “is a pretty common thing around here,” with around two or three vehicles coming in a month.
Brian Kabateck, a Los Angeles attorney is involved in a class-action lawsuit against Toyota Motor Sales, filed on behalf of an Indiana resident who watched his 2012 Toyota Tundra become a meal for rodents three times. Total damage was estimated at roughly $1,500, which Kabateck said Toyota won’t cover.
“Our contention, why soy is certainly — it’s laudable — they’re trying to be more green, at the same time, it’s becoming a potential food product for rats,” the attorney said, adding he’s not looking to make everyone rich. The suit is simply seeking reimbursement for damages and a new policy that would cover rat-damage under Toyota’s warrantee.
However, we don’t need to take the word of lawyers or service center employees. Owners are are willing to express their concerns on practically every online automotive forum. A cursory search for the term “rat” in numerous brand forums returned dozens of first-hand accounts from affected owners. Vehicles range from a Nissan Versa to a Jaguar XKR, but the vast majority share one common trait — they were built after 2005. Maybe it’s not telling, as fewer owners are worried about older cars. Still, there are decidedly fewer mentions on older threads.
Toyota claims rodent damage to vehicle wiring occurs across the industry, and the issue is not brand- or model-specific (which is true). It also noted that it was not familiar with any scientific evidence that rodents are attracted to automotive wiring due to alleged soy-based content.
Neither are we, but that isn’t stopping the public’s growing worry. Entire websites are devoted exclusively to tips on how to keep rats from eating car wiring. In the Free Press article, Janice Perzigian witnessed rodents do $600 worth of damage to her 2017 Ford Mustang. As a result, she takes time out of every day to surround the car with Pine-Sol, stuff the interior with dryer sheets, and spray down the tires with essential oils.
Forum solutions are frequently just as elaborate, often including plots to kill the varmints before they can get comfortable inside the engine bay. Our favorite reoccurring recommendation involves coating every single centimeter of wiring with hot sauce on a weekly basis.