In the cold winter months it's not unusual for rodents to sneak their way into car engines to warm themselves up. But an eco-friendly soy-based insulation being used by several automakers may be tempting these critters too much.

Rats chewed out the wiring in Art Liestman’s Honda CRV, causing hundreds of dollars in damage.

“I guess they had nibbled through the insulation and exposed the bare wires and they were short circuiting and things were going haywire,” he said.

Mechanic Max Chang at Hu's Automotive says the issue is common. He believes it’s becoming even more common as automakers like Honda, Toyota and Subaru turn to soy-based insulation.

“Oh, they love it. It’s delicious for them anyways," said Chang.

Now some car owners are fighting back, launching two class-action lawsuits against Toyota and Honda in the U.S.

"You don't make the wires out of something that's edible. A consumer purchases a car they don't know this is a potential problem," said Brian Kabatek, the attorney representing a Toyota Tundra owner.

The suits claim the automakers are aware of the problem, but have refused to cover repairs under warranty. The plaintiffs claim it's a defect and should be covered.

While Honda didn't provide a statement on the U.S. lawsuit, Toyota Canada told CTV News: "While we cannot comment on this U.S. litigation, we can say that rodent damage to vehicle wiring occurs across the industry and the issue is not brand or model specific."

So what can you do? Chang recommends insulating the wires.

"They do have the tape that insulates this type of wires, so the rodents won't eat it," said Chang.

The product looks like duct tape, but is treated with spicy capsaicin, a rodent-deterrent.

Some have said putting Bounce sheets in the area will deter rats, and moth balls can also work. You can also try predator urine, as a deterrent. It can be purchased at outdoor stores like Cabela’s, Canadian Tire and Home Depot.

Liestman's wires are now fixed and wrapped and as another precaution he put out several rat traps.

"That has been helpful in cutting down the population a bit. It's kind of an ongoing battle," said Liestman.

This isn't the first time soy-based products have caused problems in cars. Back in World War II, some U.S. states used soybean fiberboard to make license plates, which were very popular among goats that enjoyed eating them.