If you park your vehicle outside, you are exposing it to all sorts of critters that would love to use it for nesting, food storage and shelter. There are plenty of pictures online of people who've discovered there was more than an engine under the hood. In one case, the driver of an SUV started to smell a slight burning odor when she was driving. Turned out to be 200 walnuts and a lot of grass had been stored there by some industrious squirrels preparing for the upcoming cold weather.
The SUV owners had their vehicle inspected not long before this happened, but it doesn't take some animals long to set up house in what they think is the ideal spot to make their winter home. Obviously, that can create problems. Squirrels, mice, rats and other small animals can chew through hoses and wires. Plus what they store as food and nesting material may prevent engine parts from moving the way they are supposed to. Imagine a radiator fan that won't turn because it's laden with heavy walnuts. Or the fire hazard created by flammable brush on a hot manifold.
Probably the best solution is to store your vehicle inside a rodent-tight building, but that's no guarantee. Unfortunately it doesn't take a very big hole or gap for small mice or other creatures to get in. Some careful sealing with materials like cement or steel wool can reduce rodent access effectively, but they're always looking for access so you can't let down your guard.
If you're not able to store your vehicle inside, you may try spraying lavender or mint essence around the engine or in the wheel wells. Rodents don't seem to like those odors very much. If you drive your vehicle every day, you're less likely to have unwanted residents than if you leave it sit for days. In either case, if you have experienced animal problems in the past, open your hood and inspect your engine frequently.
Check with your service adviser for recommendations on how to keep animals out of your vehicle. You're not the only one whose vehicle looks like the perfect winter apartment to some critters. Preventing animals from getting to your vehicle is worth some time and expense because damage from gnawing teeth can be very costly and difficult to repair.
European Autowerks
27512 Enterprise Circle West
Temecula, California 92590
(951) 225-1131
http://www.european-autowerks.com/