We here at watermanatwork.com travel to some pretty remote places looking for fishing spots and places to ride bikes and we encounter a lot of wildlife. Deer, elk, coyotes, cougars, bears and many smaller mammals, birds and reptiles. We take precautions with food and trash to not attract any of these wild creatures but it seems we are constantly under attack by wild field mice. Mice have gotten into the cab and camper shell of my truck a number of times and caused damage from chewing and made a big mess for such a small animal.
I made a few simple and inexpensive modifications to my vehicle, a 2005 Toyota Tacoma, to keep the mice out of the cab and engine of my truck. Most vehicles will have a similar layout, this article is just to give you the general idea of what to do.
You will need some hardware cloth. It’s the screen material used to keep small animals out of gardens. I used 23 ga. 1/4″ mesh screen. Don’t use window screening because it may get clogged with dirt and block air flow. You will also need wire cutters to cut the screen material and maybe a few zip ties.
We will use the hardware cloth to block openings from the vehicle interior to the outside. The main opening is the vent that supplies air to the vehicle interior. Usually, it is under the hood, perhaps near the windshield wipers like it is on my Tacoma truck.

Measure the vent and cut the hardware cloth to size. It doesn’t have to be exact because we will bend the screen over the edges of the vent. I like to leave the mesh of the screen intact if possible.

Place the screen over the vent and do some creative bending to fit the vent without leaving any gaps or holes. Mice can get through the smallest openings. Bending the screen over the vent was fairly secure, but I used a couple zip ties to be sure the screen stays in place.

While I had everything I needed, I made a screen cover for the air intake vent of the truck engine. This is a vent from the outside of the vehicle, behind the grill or over a wheel well, that supplies air to the engine. A mouse crawled in here and made nest next to the air filter, blocking the air and making the truck run poorly. I cut and bent the hardware cloth to fit over this air intake and secured it with zip ties to prevent any further mouse nesting in the truck engine.

Not only will these modifications keep rodents out, they will also keep leaves, pine needles and debris from clogging the ventilation system. Of course you have to be sure to close your vehicle doors or the mice will simply enter through the open door.
Thank you for this! I especially appreciate the last photo, of the screen over the engine’s air intake. I know i’ve had troubles with mice in the cabin air intake, which has messed up my heating controls and propelled a small stream of insulation tufts into the cab. But that’s not as serious as mice in the engine’s air intake! They blocked the filter with a nest below it, but they made the nest with the filter material– causing a big hole in it. Now i’m concerned that the weird engine noises i’m hearing are from debris sucked into my engine!
Today i put in a new engine air filter and thought, “How do these critters get in here anyway?” and found this big 2.5″-or so- opening, pointing downward, behind the front grill. NOT screened in any way to exclude rodents. I couldn’t believe it. WHERE do these automotive designers live? Even cities have rodents! I figured i’d screen it like i did my greywater outlet– 1/4″ hardware cloth secured with a large hose clamp. It’s true the angle of the cut at the end of the pipe is a little weird and zip ties might be more versatile, so thanks for the tip. My other alternative is baling wire twisted on with pliers.
I am in wild mouse country doing more research an will update this post with more anti rodent info.
Come to Humboldt County, California, for more intensive field work with the rodent investigation! Thank you!
Thanks for the photos to follow. My service center just told me I had evidence of mice in the forward compartment of the car but, thankfully, not in the aft hybrid system. I was told I should put a similar screen over it, but I’ve been nervous to do it because I don’t want to open the car up and mess something up inadvertently as I’m pulling things out of the way to access the air intake. It would be really helpful to have a how-to guide to accessing the air intake for the ventilation and engine systems on a 2011 Prius. I’ll have to see if I can find something like that on YouTube.