Rodents just can't resist the soy-derived wire coatings used in many Subaru vehicles. The chewed up wires are costing owners hundreds, and sometimes thousands of dollars in repairs but Subaru, like other automakers, insists this isn't a defect.
Subaru prides itself on its eco-friendliness. They claim to be America’s first zero-landfill automaker[^1], and have made the switch to a more environmentally friendly, bio-degradable wire coating that is derived from soy.
But just like showing up with a tofurkey at the holidays, not all earth-friendly changes are without consequences.
The Pros and Cons of of Soy Wire Coating
The most obvious benefit of coating wires in soy-based materials is it results in less plastic in the landfill or oceans. That’s a good thing!
And the soy-based materials tend to be cheaper than their plastic counterparts, saving the automaker money. Now theoretically they could pass those savings on to the consumers, but let’s just say one way or another that saving money is also a good thing.
However there are also downsides, depending on your perspective.
The coatings are a perfect chew toy for rodents, provide excellent nesting material, are are found in near endless supply in a warm, hidden spot. If you’re a mouse, it’s the greatest thing ever. But if you’re an owner waking up to a severed fuel line, it’s a little less enjoyable.
Subaru is not the only one to make this switch or deal with the rodent-problem
Search the Internet for how to keep rodents away from your car and you’ll see everything from peppermint spray, to tape laced with capsaicin, to the less than desirable “coyote pee” option as explained in this Forbes article:
“Every night, Joann's pours a little coyote piss around her tires. "I dot my driveway with some too," she says. She also places a Coyote urine-soaked sponge inside a tin pan near the car. She's not sure it's working yet and does not want to take her car in for any more repairs until she's rid of the rats once and for all.”
If I had to do that every night it’d really piss me off.
“Plaintiff Joy Diane Shuey says she purchased a new 2015 Subaru Forester from Servco Subaru, but about a month later she took the SUV back to the dealer because of a fuel odor and an illuminated check engine light … The Servco technician allegedly discovered the fuel line and rear wiper hose needed to be replaced because they had been chewed by rats. Shuey says she paid $318.52 for repairs that Subaru didn't cover under warranty.”
So once again we’re seeing the same story line: automaker uses soy-derived products → rodents see their opportunity and cause damage → damage isn’t covered under the automaker’s warranty.
What really gnawed at the plaintiff was how later that month, she was charged $2,433.30 to replace an engine wiring harness that had been chewed through.
In general, Subaru’s response is the same as Honda, Toyota, and other manufacturers: this isn’t a defect, invest in some coyote pee, or maybe get a garage cat.