Soy-based auto wiring - A Myth?

I’ve been noticing the increased reports of automobile wiring damage by mice, rats, and squirrels. Every online news outlet and auto forum is full of testimonials about this and they attribute it to the new “green” movement of using soy-based plastic coatings on automobile wiring. All the stories are essentially the same, no new information. They say all car companies are doing it and rodents love it more than petroleum-based plastic products because it’s “food” to them and is more tasty.

But is this really true?

Rodents have been chewing on plastic and hoses and wires in cars forever. Are they doing it more now or are we just hearing more stories about it on social media?

I can’t find any scientific evidence proving what kind of plastics rodents prefer over another.

And what is this soy-based “wire coating” anyway? Is this the actual plastic wire insulation on the wire? Or is it the corrugated split plastic sheathing that encloses wire harnesses?

From the damage photos I’ve seen it seems to be that the sheathing has lots of material eaten away, and the wires have been bitten through as a side effect of eating the sheathing. It’s not as if the rodent strips and eats only the wire insulation like corn on the cob and leaves a long length of exposed copper.

Car companies don’t make their own wire, they contract out and buy it. With cursory searches I haven’t found any wire manufacturers that proudly advertise their green soy-based auto primary wire.

There have been lawsuits against Toyota and others but they were dismissed, then resurrected, but it’s uncertain where they are now.

Here’s what one Toyota response is:

“Myth: Rodents Like The Taste Of Wire Coating

You may have heard something about car makers using soy or other organic products when making car wires, and that's why rodents chew on them. However, this just isn't true. You see, rodents' chew on things to keep their teeth trimmed. The chewing on car wires gets all the attention because it's so destructive. However, rodents will also chew on plastic or anything else that's in their reach.”

https://www.captoyota.com/service/information/stop-rodents-from-chewing-car-wires.htm

Does anyone really know the truth about this?

 

I ate 21 squirrels last year. Not sure if it helped. I still see quite a few.

 

It would be interesting to know. It would be especially interesting to know how to prevent it! I spend a lot of time parked in the woods. It would really suck for this to happen when I'm camping somewhere off the grid.

 

At high country trailheads in Yosemite NP marmots have been known to eat through radiator hoses. I spread mothballs around and haven’t had problems. I’ve heard some people drive onto a large poly tarp and pull up the sides to create a critter barrier. That’s too much work for me.

 

Myth or not they chew the heck out of anything to make nests etc. Pack rats are by far the most destructive in my book. But, all rodents including rabbits will get up into engine bays as they are a "safe" place for them from predators and have many nesting type spots. I use a spray called Critter Out I believe and it has worked wonders for my Tundra as it doesn't fit in the garage.

 

I still say “snake poop” is a safe non-toxic deterrent. I have tons of this stuff….

 

Oh yeah, they’re OCD and need to chew the crap out of everything to keep their teeth worn down. Terrible damage. I just can’t figure out the soy thing. If it’s really an ingredient in auto parts and if rodents actually prefer it.

 

You have pet snakes?

 

It seems more likely that there is increasing rodent damage to auto wiring because there are a LOT more wires to chew in newer cars. If everything is electronic in a modern car, all those electronics have to be wired up. If someone was able to calculate rate of damage by ratioing it to length of wire used in cars, I bet it hasn't increased from that perspective Unfortunately that doesn't mean we can be any less paranoid about it...

 

Ya just 3. I had a breeding operation and hatched some really cool stuff. Sold at county reptile show. Non- native, non-venomous.U know a mouse will actually kill a snake if it is left in the cage too long. Lampropeltis Triangulum Hondurisis Vanishing Tangerine Amelanistic.
Possible Hybino! First ones ever hatched!!?

 

Wow. So cool. I like and respect snakes. I’m lucky my wife likes them too. When others scream and run from snakes on the trails we run towards them to take a pic or video.

 

https://topclassactions.com/lawsuit...g-attracts-vehicle-damaging-rats-can-proceed/

 

151 comments. Some, real nightmares.

 

Myth or not, mine had rodent damage on an injector wire from the dealer. And, droppings around the engine bay. Ship, warehouse, or truck rats, I guess.

I don't know if the offending creature preferred wire loom or wire insulation, but it got both.

 

Wild, right?

I always park my 4R in water because mice are scared of catfish.... I'll see myself out....

 

Thanks for asking this.

I've also wondered the same thing.

Whenever someone mentions it, it always sets off my BS meter because it just sounds like an urban myth that has been perpetuated. That's just the initial feeling I get from it. I could be wrong.

 

There are plant based plastics in all sorts of car parts. Ford has been using soy based seat cushion foam since 2010.
https://www.thedrive.com/news/15768/2018-marks-ten-years-of-soybean-seats-in-ford-vehicles

Lots of other car parts have been made from bioplastics for years and it will continue and increase.

https://bioplasticsnews.com/2019/11/26/history-bioplastics-automotive-car-industry/

https://bioplasticsnews.com/2017/03/27/toyota-denso-bioplastics-navigation-system/

https://www.azom.com/article.aspx?ArticleID=16061

I haven’t heard anything about rodents eating seat cushions, floor liners, or vent louvres. The way soybeans are processed and the chemicals that are added I can’t imagine this makes it any more attractive to pests than regular petroleum based products. Although it may be more nutritious! I’d really like to see the evidence that the class action will present about wiring.

In the meantime, mousetraps and cats in my garage protect my 4Runner. I don’t want to spray any oily repellent substance that will get gummy and attract dirt. I’m going to place mothballs and peppermint oil in pouches around the engine when parked in the woods. Or maybe order some of that snake poop from @SR5 Limited !

 

Here's a well-written article that seems to take a balanced approach to the issue...

https://www.caranddriver.com/news/a21933466/does-your-car-have-wiring-that-rodents-think-is-tasty/

Rodent nesting in cars is not a new problem in the automotive world, said Honda spokesman Chris Martin. “It is a long-established fact that rodents are drawn to chew on electrical wiring in homes, cars, or anywhere else where they may choose to nest,” Martin explained. “Honda is not aware of studies or information indicating that any of the wiring insulation or other components used for Honda vehicles are derived from substances that attract rodents or increase their propensity to chew on wiring or other components in engine compartments.”

After all of his car-wiring ordeals, does Albin believe soy-based wire insulation is to blame? “I certainly believe that soy-based wiring has exacerbated this problem,” he said. “I was curious about this as well, so I started emailing and contacting mechanics across the country. The common consensus was that rodent damage in cars has increased exponentially over the last 10 years.”

The legal system doesn’t necessarily agree, however. In response to inquiries about its handling of complaints and class-action lawsuits brought against it regarding soy-based wire insulation, Toyota responded with news that earlier this month, a judge presiding over a class-action lawsuit in California granted Toyota’s motion to dismiss the suit.

“Rodent damage to vehicle wiring occurs across the industry, and the issue is not brand or model specific,” Toyota said in a statement. “We are currently not aware of any scientific evidence that shows rodents are attracted to automotive wiring because of alleged soy-based content.”

 

Good info.
In May of this year another CA judge ruled that some part of the case can proceed. Haven’t heard about how it is proceeding though.
https://topclassactions.com/lawsuit-settlements/consumer-products/auto-news/1019074-class-action-toyota-soy-coated-wiring-attracts-vehicle-damaging-rats-can-proceed/

 

It's no myth, a good example is what happened to both my 2005 GMC Sierra and my wife's 2005 Honda Accord which were both purchased new, we had both vehicles parked in the Driveway here in Northwest Florida, and one day my wife's Accords check engine light came on, and because we get the Extended Warranty's when we buy our vehicles we drove it to the Honda dealership, it didn't take long for them to find the problem because they had been getting a lot of similar problems, Using a Scope they wormed the camera under the Valve Cover, where there was Two Wires that plug into a Anti Knock Sensor, both of which were Shredded in Half, He explained that it was and on going problem with the Accords whose sensor was manufactured using a New Soy Based Insulation, believe it or not the service Rep showed us the new Replacement which actually had yellow Tape on the Wiring that said "Mouse Proof" thankfully the $800.00+ bill was covered under the Extended Warranty plan.
Now to my Truck which we very seldom drove and even today only has 42000 miles on it was a different story, anyways as soon as we got home I tried to start the Truck, and nothing, I then Popped the Hood and started looking around, and was in a state of shock when my eyes met the Damage the Little Bastards had done underneath my hood, Every Wire leading to my Head Lights and even the back Tail Lights was shredded like someone used a Weed Wacker on them, not only that the main Wiring Harness was chewed the same way, right up to the Fire Wall where it goes into the inside if the truck, Thankfully no damage occurred to the Wires under the dash or Towing Harness (Which I Installed) and to certain Wiring under the Hood, the next day we had it towed to my local GMC Garage and they confirmed that the wires chewed were made by a company that used a New Environmentally Friendly Soy Based Wire Cover, instead of the more expensive Petroleum Based Insulation, the only wires the Little Vermin passed by and didn't chew up were made by Packard Delphi a U.S and now Mexico based Company, as for G.M.P.P picking up the Tab, I was out of luck, they refused, then the Service Manager told be he had heard that certain Insurance Company's were paying for Rodent damage like mine, I got on the Phone and called our agent, who informed me that State Farm would cover the cost, Thank God, because the Truck Bill was in the Thousands.
I did some research, and it appears that there has been one law Suit after another, against Toyota, Honda, Kia, Hyundai and GM because of the damage to the Gourmet Soy based wire Insulation, which the Rodents & Squirrels snack on like Popcorn, so if you park your vehicles where you have a large population of Rodents or Glorified Rats (Squirrels) then you will need to start parking inside, or use Peppermint Oil on the wiring, plus place some d-Con bait stations under the hood of your vehicles to kill the Population of Mice.

 

As a former auto insurance adjuster, I handled dozens of claims of rodent damage. I remember specifically covering a couple of claims involving Toyota Highlanders and a sensor wire that ran under the intake manifold. Replacing that sensor required taking the top end of the engine off and it was around $1200 to replace. There was something about that specific wire that attracted the rodents.

It's covered under your Comprehensive coverage and is a not-at-fault claim. Same as hitting a deer. Or your dog chewing up your interior. Animal caused damage is always not-at-fault.

 

Anecdotal and subjective, but we live in the woods of Virginia and the only rodent problems we've had over 13 yrs is constant mouse nests and food hording in the engine air filters and on top of the cabin filters. This applies to Honda, Toyota, and Subaru vehicles, but we've never had issues with wires being chewed. In our cases the attraction seems to be a nice warm location to build a nest in the fall, winter, and spring. Thankfully the new 4R lives in the heated/cooled garage with 2 cats that attack anything that moves.

 

Holy sheeit. So sorry for your pain. It’s an epidemic out there, lots of reports of damage. A buddy of mine has a similar story. It’s been going on in cars and house wiring forever but it seems to have accelerated recently. I suppose we could try to wrap all wire bundles with Honda’s capsaicin tape, but that’s not so easy to do. Maybe the lawsuits and bad publicity will make the car manufacturers finally address it.

Still, if anyone has documentation of this soy wire insulation, or sheathing, which manufacturers make it, specifications, and part numbers, please report it here. Or any scientific studies or experiments confirming what rodents prefer. As bad as it is all we still get is verbal opinions and hearsay about soy coatings on wires being the cause.

 

I have also read that its not only the Wire Insulation made from Soy Bean Based By-Product on the Rodent menu, they also made some Duct Hoses and some other Engine products like Air Cleaner Covers out of the stuff, and the Mice are Snacking away.