Bugs, Squirrels, Mice: Pest Control in Cars

Winter is coming. Rodents want a place to nest. That could be in your warm engine compartment. I’ll tell you how to keep mice out of your car!

Person washing their car
Person washing their car

It’s a disheartening feeling to find out that your car has been invaded by a pest, whether it’s bugs, squirrels, or rodents. The car that you spend all that time washing and waxing. The one that you park at the end of the parking lot to avoid door dings. But the mice, rats, squirrels, cats, opossums, and other small animals don’t care about that. They see a nice spot to nest.

I ran into that situation myself a few years ago. I took my Pontiac Vibe in for a routine oil change. The mechanic asked if I had a dog or a cat. I said, ‘No,’ and stared back, unsure why I was being asked that. It turns out that he found large handfuls of kibble stowed away behind my glove compartment. Even after he cleaned it out, I found about a dozen more pellets once I got home.

Animal food in engine bay
Animal food in engine bay

We weren’t sure what kind of animal was getting into my vehicle. My neighbor had an outdoor cat, so it could have been one of them. They left food out on the front step for the cat, too, so it could have been any kind of animal stealing that outdoor cat’s outdoor food and burrowing it in my engine compartment.

As you’ll see in this article, there are plenty of spaces for a rodent to hide in your vehicle, but there are also plenty of ways to stop it from happening.

What, How, Where, and Why?

Squirrel in a wheel well
Squirrel in a wheel well

All kinds of rodents and small animals can find their way into a vehicle. Mice, rats, chipmunks, squirrels, opossums, cats, racoons, and snakes have all been found under the hood before. When car doors are shut and locked, people have a hard time getting into a vehicle, but animals? Not so much. They get in through all the openings you may or may not expect.

They climb up the tires, through wheel wells, and go from there: over the pedal shaft, into the steering column, or into vents. They can also get in through the tailpipe. There are more small openings in the undercarriage, too. Holes in the body panels offer multiple ways to get in.

Raccoon by a car tire
Raccoon by a car tire

Once inside a vehicle, the critters go to a number of spots. Animals are usually trying to find a warm spot to rest, especially in the winter months, so they’ll purposely head into vents, air filter boxes, or into the dash. Just imagine all the spaces they could find under the hood of a Ford F-150 Raptor! They naturally gravitate towards batteries, though, since they’re a source of heat.

There is some debate about whether the materials used in vehicles newer than 2008 actually attract rats and mice. Many manufacturers use bio-plastics made of a soy byproduct, which can attract squirrels, mice, and rats. Using those biodegradable materials to reduce waste is great for the environment, but could have unwanted side effects.

Danger Mouse

Vehicle air vents
Vehicle air vents

Danger Mouse was actually a fun cartoon character from the 1980s, but mice (or other animals) inside your vehicle can be dangerous, too. Besides the hazard presented to the animal, the vehicle’s integrity could be at risk. Rodents tend to nibble on electrical wiring in an engine compartment. That can short circuit any number of important vehicle functions.

Rodents carry disease, too. If a rodent is taking shelter in a ventilation system, then all those germs can be output into the cabin and the lungs of anyone in the cabin. There aren’t a lot of examples of this happening, but people can get Hantavirus Pulmonary Syndrome (HPS) from rodent urine and droppings that are stirred up into the air.

The dust, dirt, and straw that animals are bringing into the engine compartment with them can also cause allergy issues for a driver.

Noticing the Warning Signs

Damaged car wires
Damaged car wires

Many people will go their entire lives without even knowing a rodent may have been in their car. That may be because there may be some signs they’re missing.

Odor is one of the biggest signs that there may be more than engine parts under the hood. For anyone who hasn’t smelled a dead rodent before and is concerned they may not recognize the smell, don’t worry: you’ll recognize it. It’s a distinct, rancid smell that doesn’t go away after a couple of sniffs. Trust your gut on this. If you smell something that you think could be a dead rodent, chances are you’re right. Do some investigation of your own or take it into the shop to have them look the vehicle over.

Bits of food is one of the biggest signs. Seeing some pet food on the ground, in the garage or driveway, may be unusual, but is easy enough to shake off. Someone may have dropped it. The dog or cat may have gotten into it. The alternative is that a rodent may be burrowing its away in your engine.

Bird nest in engine bay
Bird nest in engine bay

It’s not just food animals bring with them. They also bring things like nuts, cones, grass, straw, and anything else useful for making a nest. Those things are common in the country, but a trail of straw in your paved suburban driveway is an indicator that more investigation may be required.

Electrical shortages or malfunctions are another indicator that a rodent may have taken up residence under the hood. Maybe the blinker isn’t working all the time. Or it could be those shortages are from frayed wires that were nibbled on.

Footprints are another sign to look out for, but those are harder to spot. They are much easier to spot in the snow, of course. Or on the dust in the engine. Be on the lookout for droppings, or urine spots, too.

Prevention

Person vacuuming their car
Person vacuuming their car

Here we are! It’s time for the good news! A rodent issue doesn’t have to be an ongoing issue. It doesn’t even have to be an issue to begin with. There are a lot of ways to prevent or mitigate rodents claiming your vehicle as their home. Some of the factors below aren’t within everyone’s control, but some are.

The easiest way to prevent a rodent invasion is by keeping your car clean. Don’t leave that Jimmy John’s bag on the floorboard of the back seat. Throw it away, instead. If you drop some granola bar crumbs on your lap on the commute to work, vacuum them up later. Rodents are looking for a food source, so why make it easy for them to find food?

Where a vehicle is parked is another determining factor. Dumpsters, gardens, bird feeders, and bushes can all attract small wildlife. Parking next to those things isn’t always avoidable, but, consider other options if there are any.

Car parked in a garage
Car parked in a garage

Of course, parking inside a garage helps. Rodents can still get into a garage if there are cracks or the openings aren’t sealed properly, but chances of them getting into a vehicle are decreased if the vehicle is in a garage. It’s one more barrier for them to overcome.

Parking in alternate spots, at work, for example, is another way to deter your engine from becoming a permanent home. That makes it less convenient for rodents to return regularly.

Keeping the area around a vehicle clean can be just as important as keeping the inside of it clean. Piles of fall foliage scattered around the vehicle make a nice pathway to the wheel wells. You know where the rodents go from there. The same thing goes for birdseed and dog or cat food inside the garage. Easily accessible food is an invitation for a rat to take and place inside an air cleaner or glove compartment.

Peppermint oil
Peppermint oil

There’s a long list of rodent repellent available as well. Peppermint oil is a common one. Throw packs filled with organic repellent is another. Be warned: the odor of the bagged repellent is strong! I’ve used them before. They don’t smell bad, but they are powerful! You can’t necessarily spray your components with this, or place a throw pack under your hood, but these are useful tools to prevent rodents from getting near the vehicle in the first place.

Lastly, don’t leave the car unattended for a long period of time. A stationary vehicle makes an appealing home for a four-legged creature seeking a safe hideout. Even if the vehicle isn’t used daily, using it a few times a week will help prevent a permanent refugee in the engine compartment or any other part of the vehicle.

Known Issues

Steam cleaning an engine bay
Steam cleaning an engine bay

If there is already a known rodent issue, setting traps can help eliminate that problem. Closing up gaps in the garage using a rodent barrier kit is another option that will stop the situation from getting worse.

Steam cleaning the engine compartment isn’t a bad idea either. If a rodent has been eating in that area, it’s a safe bet there are droppings and urine left over. Clean it and start fresh.

Person inspecting their car
Person inspecting their car

Getting rid of an issue is always harder than preventing one from happening to begin with, so taking care of a vehicle and spending a little extra time looking for warning signs can prevent headache (and a couple of hefty cleaning bills) later.

Taking good care of a car is the key to a lot of things, isn’t it? Take a look at some of our other articles for even more car maintenance advice. We’ve got a full section that covers all kinds of topics from, ‘Why Won’t My Car Start’ to ‘How to Clean Car Seats.’ We’ve also got the ‘Top 10 Tips to Winterize Your Car’ and ‘A Simple Checklist for Taking Your Car Out of Storage.’ You may be surprised what you learn.

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Jesse Batson

Jesse Batson earned his journalism degree from South Dakota State University. No stranger to newsgathering and reporting, Jesse spent 13 years in TV news. 10 of those years were spent working in Charlotte, NC, home of NASCAR. A highlight of his time there was being able to take a lap around the Charlotte Motor Speedway. His interest in vehicles, starting with Matchbox cars, a Big Wheel, and the Transformers, evolved into taking photos of motocross events. Now, he puts his research skills to use on car culture, reviews, and comparisons.

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