# Martens and mice under the bonnet: signs and protection _Updated: 8 November 2026_ **Short answer:** Martens and mice get under the bonnet because the engine is warm and sheltered. They chew cables, rubber hoses and insulation, and the damage is often noticed only when a warning light comes on or the car will not start. A device under the bonnet with metal plates reliably protects against martens: it drives them off with a mild electric shock. > **The service we recommend: Marten and rodent protection** A marten and rodent repeller under the bonnet, with the engine bay washed. We tell you the price when you tell us the model. [More about the service](https://autoindustrija.rs/en/services/marten-protection) ## How to tell a marten has been in your car These signs tell you a marten has been under the bonnet: - **Paw prints on the bonnet:** A marten walks over the car and leaves paw prints on the paint. - **Chewed or torn insulation under the bonnet:** A marten tears the foam and insulation that dampen engine noise and heat. - **A chewed cable or rubber hose:** The cable or hose has tooth marks, or it is bitten right through. - **A warning light comes on or the car is hard to start:** A chewed sensor cable causes a fault, and sometimes the car does not start at all. - **The engine jerks and runs unevenly:** The marten has chewed an ignition cable. - **Coolant or washer fluid is leaking:** The fluid hose has been bitten through. A marten is not noticed straight away, and its traces often go unnoticed. The later the damage is found, the more expensive the repair. ## Why a marten gets under the bonnet and why it bites For a marten the engine bay is warm, dry and sheltered. It rests there and hides food, and young martens play there. While they explore, young martens chew cables and hoses. A marten leaves its scent wherever it goes, even when it just walks over the bonnet. When another marten smells that scent, it gets aggressive and bites cables and hoses especially hard. This happens when you park in several places, so two martens get under the bonnet within a short time. Martens are active all year, most of all in spring and autumn. In spring, before mating, martens fight over their territory, so biting out of aggression is most common then. In autumn they look for a place to sleep. Serbia has about 15,000 stone martens, according to an estimate by the Statistical Office of the Republic of Serbia. They live in suburbs and in town centres too. In Germany, martens caused 235,000 claims on comprehensively insured cars in 2023 alone. ## What a marten chews and what happens to the car A marten most often bites parts made of rubber and soft plastic. Each chewed part causes a different fault: - **Ignition cable:** the engine jerks, and unburnt fuel damages the catalytic converter. - **Coolant hose:** coolant leaks and the engine can overheat. - **Thin rubber hose on the engine:** the car loses power and can switch to limp mode, in which the engine runs with little power until the fault is fixed. - **Rubber boot on a drive shaft or the steering rack:** the drive shaft turns the wheel, and the steering rack turns the wheels when you turn the steering wheel. The rubber boot protects their joints. A chewed boot is not noticed straight away, but dirt and water get in and the joint is damaged. This can be dangerous while driving. - **Power cable or sensor cable:** a warning light comes on, something stops working or the car will not start. ## What helps against martens in the car An electric shock device reliably drives a marten off. Other protections help, but each has its limits: - **Electric shock device:** Metal plates under the bonnet work like an electric fence. The voltage is several hundred volts, but the current is weak and harmless. A marten that steps on a plate gets a mild shock and leaves. Fitting it is a job for a professional. [More about marten protection](https://autoindustrija.rs/en/services/marten-protection) - **Sound device:** It drives the marten off with a sound that keeps changing pitch. It is easier to fit, but sound alone drives a marten off less well than an electric shock. Some people can hear the sound and find it annoying. - **Device with both:** It has plates and a speaker. The sound drives the marten off, and a plate gives a shock if the marten still steps on it. - **Protective sleeves around cables:** Hard plastic around the ignition cables. They do not protect hoses or the rubber boots on the drive shafts. - **Closing the engine from below:** A panel under the engine keeps the marten away from cables and hoses. For some models it comes as factory equipment or can be added later. - **Wire mesh under the car:** It is laid under the car when you park. It sometimes keeps a marten away, but it does not block the way reliably. - **Washing the engine bay:** It removes the scent a marten has left, so another marten does not smell it. - **A garage:** A car in a closed garage is best protected while it stands there. Outside, at work and on the road, the device under the bonnet protects the car. ## Does marten spray help Marten spray helps only sometimes and only briefly. The same goes for scents, dog hair and other home remedies. A marten stays away from them for a while, but not for good. The scent of a marten that has been under the bonnet stays there and attracts another marten. Washing the engine bay removes that scent, and a device with plates reliably drives the marten off. ## Mice in the car: where they hide and what they chew Mice and rats chew cables too. They chew them down to the wire, so a sensor reports a fault, the headlights cut out or a fuse blows. Droppings tell you that mice or rats have been there. Mice and rats are more likely to nest in a car that is not driven often. You will most often find a nest in these places: - In the engine bay insulation, between the battery and the body and near the wiper motor. - Under the air intake hose and in the air filter. - In the ventilation and heating ducts. - In the boot, around the spare wheel. - Under the seats and in the glovebox. A nest in the air intake causes a bad smell in the cabin. The engine may then pull less, run unevenly or not start. When there is a lot of nesting, the filter is replaced, and sometimes the hoses, ducts and fan as well. Do not vacuum or sweep droppings and nests while they are dry. You catch hantavirus fever when you breathe in dust with droppings and urine of infected rodents. The Batut Institute recorded 127 cases in Serbia over 10 years. So clean in this order: 1. Open all the doors, the boot and the bonnet and let the car air out for 20 minutes. 2. Put on gloves and a long-sleeved top. 3. Spray the droppings and the nest with disinfectant until they are fully soaked. You can also use a mix of bleach and water, 1 part bleach to 9 parts water. Leave it for 5 minutes. 4. Pick them up with a paper towel and put them in a rubbish bag. 5. Wipe the spot where they were once more with disinfectant. 6. Tie the bag and throw it away. Rinse the gloves, take them off and wash your hands with soap. Do not leave food in the car, because it attracts rodents. Manufacturers say the devices under the bonnet also drive off mice and rats. ## What to do when you find damage - If the engine jerks, is hard to start or the engine warning light is on, do not drive on without a check. Unburnt fuel damages the catalytic converter. With diagnostics we find which sensor or cable is not working. [More about car diagnostics](https://autoindustrija.rs/en/services/car-diagnostics) - If coolant is leaking, do not drive, because the engine can overheat. - If the headlights cut out or a fuse blows, a cable may be chewed down to the wire. We find and repair such a cable. [More about the auto electrician](https://autoindustrija.rs/en/services/auto-electrician) - The rubber boots on the drive shafts should be checked even when the car drives normally, because a chewed boot is not noticed while driving. - Photograph the damage before the repair. - After the repair, we wash the engine bay and fit the device, so another marten does not smell the old scent and chew the new cables. With some insurers, damage from rodents and animals is an add-on to comprehensive cover, agreed and paid for separately. Check your policy to see whether it has it. If it does, report the damage to the insurer straight away. Do not replace the chewed parts until the insurer has seen the car, unless the repair is urgent to stop the damage getting worse. ## Frequently asked questions ### Can I catch a marten with a trap? No. Under the Serbian rulebook on game species protected by a closed season, the stone marten and the pine marten are game protected by a closed season. The Law on Game and Hunting forbids hunting with snares and traps. Outside hunting grounds a marten may be hunted only with the consent of the Ministry. That is why a marten is driven off, and a device under the bonnet does this without harming it. ### Can a marten damage an electric car? Yes. A high-voltage cable has thick insulation, but a marten can still chew through it. The car then reports the fault itself. There is no risk of electric shock. The high-voltage system is well protected and switched off while the car is parked. A chewed high-voltage cable is not repaired, the whole cable set is replaced, so the damage is expensive. ### Does a marten device drain the battery? The device uses very little power while the car is parked, and it is switched off while the engine is running. Devices with battery protection switch themselves off when the battery voltage drops too low. ### How much does marten protection cost? It depends on the device and on how many plates your car needs. The price includes the device, washing the engine bay and fitting. Have a question about your car? Message us on WhatsApp or call 067 774 1606. ## Read also - [Getting your car ready for winter: 8 checks](https://autoindustrija.rs/en/advice/winter-car-checklist) - [Car battery in winter: why the car won't start and how to protect it](https://autoindustrija.rs/en/advice/car-battery-in-winter) - [Car battery: which one to choose and what to look out for](https://autoindustrija.rs/en/advice/which-car-battery) --- Page on the website: https://autoindustrija.rs/en/advice/marten-and-rodent-engine-protection auto-industrija, Belgrade. Phone and WhatsApp: +381677741606. E-mail: kontakt@autoindustrija.rs.