How to Prevent Rodents from Entering Your Car Engine

Open your car, turn the key, engine starts but all the lights go up like a Christmas tree? Or worse, engine doesn’t start at all.
You might be one of the “lucky” ones that has a problem with rodents

It can happen to anyone and it happens fast, regardless of parking in the garage, storage or outside…some mice just simply find a way to enter you engine bay.

Why is this happening?

There is a little rodent, called the wood rat or pack rat which is notorious for building nests from what they collect from nature or even from trash or treasures from humans. This little one usually visits engine compartments to find a warm and dark shelter or simply is drawn by all the colored wires and shinny surfaces of a car engine (especially a newer one).

Wood rat is described as having “such an innocent look, is so easily approached or expresses such confidence in one’s good intentions” because it’s a harmless and curious little creature that won’t attack you. The only downside is that it loves different wire colors and textures, warm and dark, hard to reach places.

Research show that starting with the year 1990, car manufacturers started to be forced by governments around the globe to include bio-degradable components to cars in order to recycle a higher percentage of the car after it is sent to the junkyard.
Nowadays some components include in their composition:

  • Soy
  • Rice Husks
  • Wood
  • Sugars
  • Sweet smelling substances likve Vanilla
  • Peanut Oil
  • Straw

No wonder these little creatures started to add car engine components to their late night snack list. Although not all components have a nutritional value to them, most of them are harmless and appealing to rats. Rodents gnaw all the time, their teeth grow rapidly throughout their life (up to 2.9 millimeters a week) and they need to sharpen and wear them down.

How much damage can a little rodent do?

Size does not influence impact here. Little rodents that stay overnight under your hood might cost you repairs in excess of $500-$1000 since most new cars are packed with electronics and tons of wiring. They usually chew off insulation and other elements to create and consolidate a nest, then they move to chew wires they find interesting. Sometimes they chew them through and your car might not start or will perform badly.
Other times only the insulation has to suffer which is cheap to fix but often hard to find. This cheap fix however might become an expensive fix if wires touch and short-circuits appear.
Sadly most of the users discover that something is wrong after they drive off and start to experience a “burning smell” that usually comes either from a short-circuit that melted wires or even worse components burning out or the nest catching fire ( the little mouse uses insulation and other debris to create his little nest)

Also an important aspect to keep in mind is that rats carry diseases with them. One important one to note is Hantavirus.
Hantavirus is a virus that humans can catch and in spreads by air.

How to Prevent Rodents From Entering My Car Engine?

This is tricky because some techniques work and some do not. There is a certain degree of subjectivity regarding area, mice type and maybe luck.

A few techniques you might try :

Protect car from rodent damage

  • Leave the hood open . The rodents are searching for a dark and warm place to nest. Hood being opened reduces warm and dark areas so it can potentially discourage
  • Seal off or remove hiding places near your car. This includes places as shrubbery or vines. Also if you store your car in a garage it’s best to block entrances rats could use or spray them with substances that they hate
  • Block entrance to vehicle engine. Some people use traps around the car or on top of the wheels since that’s the route the rat uses to get into the engine compartment
  • Use electronic deterrent devices such as devices that use ultrasounds or strobe lights. The light and ultrasounds are elements that annoys a rat.
  • Use smells that rats don’t like . You can use peppermint oil, powdered fox urine, cat/dog hair, red pepper, laundry dryer sheets or used cat litter.
  • Use your car every once in a while. Having a car sit will create an invitation for a permanent new resident
  • Place a bucket of mothballs under the cars engine
  • Don’t leave food in your vehicle

Got rid of rodents. How to repair what they left behind?

From a technical standpoint you should do a thorough inspection to see what components in the engine bay were affected. Most of the time they chew engine dampening insulation, wire coverings, plastic, carpeting or air conditioning& heating ducts.

Asses the damage and decide if you can fix it yourself or if you need to take it to a car repair shop.
Some of the times this damage can be included in the “act of God” clause in your comprehensive car insurance. If you’re not lucky enough to have a comprehensive plan, you might need to pay for the whole repair.

From a health standpoint you should make sure that you have a mask on your face when you do the inspection or any repair.
You can contact the Hantavirus from mice or mice residues. It’s important not to sweep or vacuum rodent or droppings as airborne particles carrying the virus might be inhaled.

If you have an extreme case of mice infestation it would be best to take your car to an auto detailer that may use an ozone-generating machine to kill off viruses and bacteria.

If the infestation is not that bad you can do the following to clean the infected area with a liquid disinfectant:

  • Wear plastic or rubber gloves
  • Mix a gallon of water with 1/2 cups of household bleach and create 2 batches. Spray on batch the affected areas until they are very wet
  • Allow it to action for about 5-10 minutes
  • Wipe the area down with a paper towel and safely discard of it
  • Sponge the affected area with bleach
  • Soak the gloves in the 2nd batch of the bleach mixture before removing them
  • Wash hands with soap and warm water after removing the gloves
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Tech Guy

Automotive enthusiast, passionate about Jeeps, hot-rods, turbos, performance, efficiency, diesels, fuels, high performance oils, additives and anything with an engine.

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