10 Best Rodent Repellent For Car Engines 2025 in the United States

Grandpa Gus's Natural Mouse Repellent Pouches use a natural blend of peppermint and cinnamon oils to keep mice away, making them a good choice if you want a chemical-free solution around your car engine or storage areas. The pouches last between 1 to 3 months, which provides decent protection without frequent reapplication. Since they rely on essential oils rather than traps or poisons, they are safe for car parts and won’t cause damage or leave harmful residues. Application is very easy—you just place the pouch where you want protection, and there’s no mess or cleanup needed.

Besides repelling rodents, they also freshen the air with a minty scent, which some users may find pleasant. On the downside, the scent may not be strong enough in large or heavily infested spaces, so it might work best in smaller or less exposed areas like engine compartments or enclosed storage. Also, while the plant-based formula is biodegradable and non-toxic, some people sensitive to strong fragrances may find the cinnamon and peppermint smell a bit overpowering.

This product suits those looking for a natural, low-maintenance way to deter mice, especially if you’re concerned about chemicals near your vehicle. It is less ideal if you need a heavy-duty solution for severe infestations or very large spaces.

The Mighty Mint Gallon Rodent Repellent Spray is designed to protect your vehicle's interior and engine from rodent damage using natural ingredients. Its large volume of 128 fluid ounces ensures that you have plenty of repellent to cover multiple applications or larger areas.

The natural formulation is a significant plus, as it is safer for car components and environmentally friendly. This makes it a suitable choice for those who are environmentally conscious and want to avoid harsh chemicals. The pleasant smell is an added bonus, making the application process more enjoyable.

The spray format allows for easy and precise application, which is convenient for targeting specific areas under the hood or inside your vehicle. The Mighty Mint Rodent Repellent seems like a good fit for those seeking a natural, easy-to-apply solution with a pleasant scent, but users might need to reapply it more frequently in high-infestation areas.

Fresh Cab Botanical Rodent Repellent uses a plant-based balsam fir oil to keep mice away, making it a natural and non-toxic option compared to chemical repellents. It is designed for use in enclosed spaces, including car engines and storage areas. The repellent lasts up to 90 days in areas without active infestations, but if rodents are already present, you'll need to use more pouches and replace them every 30 days.

This product is very easy to apply—just remove the plastic wrap and place the pouches where needed, no mess or special tools required. Its safety for car components is good since it doesn’t rely on harsh chemicals, reducing the chance of damage to wires or plastic parts. Environmentally, it's a strong choice, being USDA BioPreferred, EPA-registered, and made by a company with a low carbon footprint using ethical labor practices.

Because it relies on scent, its effectiveness might be less in open or highly ventilated engine compartments compared to closed storage spaces. It is more suited for prevention and light infestations rather than heavy rodent problems. If you want a gentle, eco-friendly way to help protect your car engine from mice without using sprays or poisons, Fresh Cab is a solid option, but for serious infestations, you might need additional methods.