can a mouse get in a car ventilation system

[McOmar]

Yes, a mouse can definitely get into a car's ventilation system. These small rodents, capable of squeezing through openings as tiny as a dime (about 1/4 inch or 6 mm in diameter), often enter through the vehicle's fresh air intake vents located near the windshield wipers or through gaps in the firewall and undercarriage. Once inside, they can nest in the ducts, causing clogs, unpleasant odors, and potential damage to blower motors and filters. This is a common issue in colder months when mice seek warmth and shelter.

The primary entry point is the cabin air intake, which is designed to allow air flow but isn't rodent-proof. Mice are attracted to the warmth of the engine bay and can easily climb up tires or hoses to access these vents. Signs of an infestation include scratching noises when the fan is on, a musty smell from the vents, or visible nesting materials like shredded paper or insulation.

To prevent this, regularly inspect and clean the area around your windshield wipers and under the hood. Use rodent repellents like peppermint oil-soaked cotton balls or commercial ultrasonic devices, but avoid mothballs as they can be toxic. Sealing gaps with steel wool or metal mesh can be effective, as mice cannot chew through metal. If you suspect an infestation, have a professional mechanic inspect and clean the ventilation system to avoid spreading allergens or causing further damage.

Here are some common signs and their implications:

Sign of Mouse Infestation	Description	Recommended Action
Scratching Noises	Heard when blower fan is active, indicating movement in ducts.	Turn off system and inspect immediately.
Unpleasant Odors	Musty or urine-like smells from vents, often from nesting materials.	Use an HVAC cleaner or seek professional cleaning.
Reduced Airflow	Blockages in ducts from nests or debris.	Check cabin air filter and ducts for obstructions.
Visible Droppings	Small, dark pellets near vents or under seats.	Clean with disinfectant and wear gloves for safety.
Nesting Materials	Shredded paper, insulation, or fabric in air intake areas.	Remove nests and seal entry points to prevent recurrence.

Regular maintenance, such as changing the cabin air filter every 15,000 miles, can help detect issues early. In severe cases, mice can chew through wiring, leading to expensive repairs, so proactive measures are key.

[ZaneAnn]

I found a mouse nest in my car's vents last winter—it was a mess. They got in through the air intake near the windshield. Now, I park in a garage and use peppermint oil around the tires. It's cheap and keeps them away. Just check under the hood every few weeks; if you see droppings, act fast before they cause damage.

[DelWilliam]

As someone who's worked on cars for years, I've seen mice wedge themselves into ventilation systems through gaps as small as 6 mm. The cabin air filter housing is a common entry point. To fix it, you'll need to remove the filter and vacuum the ducts. I recommend using metal mesh to cover openings—it's durable and prevents chewing. Regular inspections can save you from costly blower motor repairs down the line.