Every week, at The Garage, we get at least two customers who are experiencing strange problems with their cars – caused by rats and other rodents. The fact is that the push for ‘greener’ cars has had the unintended result that they are becoming an increasingly appealing part of a rodent’s diet. Our furry friends are being dished up a delicious à-la-car(te) menu and they are lapping it up.

We don’t suggest that you chew on your seat cushion next time you are out on the road and feeling peckish, but they may contain soy foam – which rats regard as a tasty snack and great for nest-building. The insulation on your wiring may contain peanut oil or something similar. Other parts may contain tasty ingredients like sugar, rice husks, something that smells like vanilla and straw. Of particular appeal to rats is fabric made from recycled yarn, which is another material favoured by an industry diligently trying to demonstrate how environmentally responsible it has become.

Most of the serious problems we are asked to address concern wiring. In an effort to get away from being dependent on oil-based products, many manufacturers are using ‘organic’ and plant-based materials for items such as wiring harnesses, air conditioning and heating ducts and plastic bottles to hold various fluids. For a home-hunting rat, a nice, modern engine is a very desirable residence. Rent-free and fully heated – what more could a rat want? The engine often has a plastic cover over it for added privacy, and there is good stuff to gnaw on just steps away, all around it.

Flossing for survival

I say ‘gnaw’ because, while rats like the taste of soy-based wiring, they also use it for their dental maintenance routine rather than digesting it. The reason for that is that their teeth need to be continuously managed so they don’t grow too long. A rat’s teeth can grow more than 2.5 millimeters per week, so gnawing is a necessary activity to keep them short, sharp and effective. Their teeth are also harder than copper wire and even iron, so a few bits of wiring pose no problem. They can chomp straight through them.

And just because your car is ten years old, don’t think this problem won’t affect you. Japanese OEMs have been using soy in their wiring harness covers for over 30 years. Because of the way cars are built and parts are sourced these days, this problem affects American and European cars as well – in both urban and rural settings.

Edible tires are coming!

Ironically, the problem is only likely to get worse as manufacturers seek more and more ways to meet environmentally-motivated demands and pressures. There is even talk, for instance, of Bridgestone developing tires made from guayule shrubs that grow plentifully in the southern US states and northern Mexico.

Be alert to the signs

What to do about it? That’s the big question that has yet to be answered definitively. If you Google the problem, you will find all sorts of temporary cures, from peppermint spray to scented laundry dryer towels. But preventative measures are best, of course.

When a rat chews on a wire, it could be weeks or months before you discover it. Once the damage is done, a sensor will most likely set a code and, depending on the nature of the problem, your car will probably revert to ‘limp-in’ mode. That means the computer will allow you to get to The Garage to have the problem fixed, but not much more than that.

So, it’s a good idea to pop the hood every now and then and take a look, and to bring the car in for a thorough inspection on a regular basis (we suggest every three to four months).

The high cost of rodent denial

This is a serious problem for motorists, for two main reasons.

Firstly, while manufacturers are pushing to demonstrate sustainability, they are also building into their products parts and equipment that are known to be susceptible to rodent damage, on an increasing basis. Should we be concerned about the safety implications? It would seem to be irresponsible if the desired perception of sustainability should knowingly compromise the robustness and safety of the product.

You may not be surprised to know that, although manufacturers are very much aware of this problem, rodent damage is not covered by their warranties. However, many will happily sell you temporary ‘fixes’ should you get a problem. And don’t go crying to your insurance company; they don’t want to know, either. You can reasonably assume that you will have a rodent problem at some point, since there are more rats than people on this planet and there is certainly a family or two living near you.

The second reason this is a serious problem is that rodent damage can be extremely costly to remedy. At the worst end of the scale, we have heard stories of cars being totaled and even going up in flames as a result of shorts and other damage caused by rats. At best, it can cost a few hundred dollars, but may run to several thousand, to fix a wiring problem. And rats are not discerning about old or new, cheap or expensive cars.

Some examples: repairs to a 2014 Tesla Model S in Belgium recently cost $12,750, due to wiring damage; a 2012 Hyundai Accent had $6,300 spent on it in St Louis; and a 2014 Subaru Forester in New Jersey (with only 7,000 miles on the clock) was completely burned out due to suspected rodent damage to fuel lines (with other rodent damage having previously been fixed).

So, go check under your hood and tell us if you find any signs of rats!

Also, leave a comment below, particularly if you have had rodent problems with your vehicle, or call us if you would like to arrange a bumper-to-bumper inspection.