Rodents in Cars, Garages and Sheds
A car that sits in the driveway or a garage for a few weeks can turn into a nest. University of Arizona Extension names engine compartments of seldom-driven cars as a woodrat nesting spot and says woodrats are notorious for chewing wiring in cars and appliances. Mice do the same in campers and trailers over the winter.
If the check-engine light comes on and you find sticks or shredded insulation under the hood, you've probably got a pack rat.
What to check
Open the hood and look at the top of the engine, the air filter box and around the battery. Look in the cabin air filter. Check the garage corners and the shelves for nests and droppings.
- Sticks, leaves or cactus bits on top of the engine
- Chewed wires or hoses
- Droppings in the air filter box
- Nests in boxes, tires or seldom-used gear in the garage
Safety first
The state health department says to air out stored vehicles and closed buildings before you go in. Wear gloves, and treat droppings and nests the way you would anywhere else: soak them with disinfectant before you touch them. The cleanup page has the steps. Wiring damage is a job for a mechanic.
Keeping them out of the garage
Most garages leak at the door seal and the bottom corners. Fixing those, keeping feed and birdseed in metal cans, and moving firewood away from the garage wall all help. A provider can trap the rats and seal the building. See rodent exclusion.
Questions
Do repellent sprays under the hood work?
Extension mentions a balsam fir oil repellent that seems to help with woodrats. It's a supplement to trapping and sealing, not a replacement.