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How to Keep Mice, Rats and Other Rodents out of Your Car Engine

Rochelle has experience with wild critters and gardening adventures while living the simple life in a rural area for 20 years.

Are They in Your Vehicle?

Rodents are everywhere, and they can do considerable damage when they invade your vehicle. They might decide your car is a safe place to make a nest and a handy site to store food. If you can discourage them, you may win the battle.

There are dozens of techniques used to prevent mayhem by the destructive critters, and they work especially well in combination. Multiple lines of defense seem to work best.

Steps to Take

  • Leave the hood up. Rodents are looking for a dark place to nest. This idea could help discourage nesting, but may not be the ultimate solution.
  • Hide your dog food, cat food, and birdseed. Dog food is the gold standard of rat society. Rats will stuff pounds and pounds of it into the air cleaner, glove compartment, or other empty spaces in your car.
  • Remove or seal off rat hiding places near the car. Cut down nearby thick shrubbery and vines where they can hide. If you have a garage, block rat-sized entrances to the building, or spray openings with substances that rats hate (see below).
  • Block small entrances to the vehicle engine compartment. Some car owners place traps around the vehicle or on top of the wheels, since rats climb wheels to get into the engine. Some block engine openings with wire screen.
  • Use electronic deterrent devices. Rodents can hear ultrasounds that we cannot, and it annoys them. Some learn to ignore it. Those with strobe lights like Mouse Blocker or Rid-a-Rat may work for longer periods, as they disrupt the darkness that rats prefer.
  • Make your engine and its entrances smell bad, at least to rats. Motorists have had success with peppermint oil, powdered fox urine, used cat litter, cat hair, dog hair, Pine-Sol, Irish Spring soap, red pepper, and laundry dryer sheets. The people who make "Rataway" tell you to spray it on all the wires in the engine.
  • Do not let the car sit unused. Drive it once in a while to discourage rats from doing mechanical or electrical work.
  • Finally: use traps to remove the rats who get through. The old-fashioned snap traps still work. Glue traps work too but may torture the rat. Humane cage traps may work, but relocating the varmints can be a temporary fix.. Toxic baits do kill rats eventually, but are likely to also poison predators, including domestic animals and pets.

Some Techniques Work (For Some People, Some of the Time)

It is a myth that small autos are powered by hamsters running on exercise wheels, but it is an unfortunate fact that rodents can live and create mayhem in engine compartments. In fact, the damage done to vehicles by mice, rats, and their many cousins can be considerable.

Gnawing wires, ripping out insulation for nesting materials, or squirreling away caches of nuts and trash in car and truck engines can destroy some of man's most sophisticated transportation technology and cause significant financial loss.

This is especially true if you live in a rural area. You need your car to get to your job or to go shopping, but wood rats and other critters want it for their homes.

Run! The hood is open!

Run! The hood is open!

Rodents Can Move in Quickly

Rural people know that a seldom-used old car may be taken over by rodents, but the critters can also get excited about brand new cars. In less than 24 hours, they can destroy much of the wiring.

Some plastic insulating material now being used in cars seems especially tasty to the tiny invaders. When mice chew the insulation off wires that connect batteries, alternators, or anything electric to anything else, they cause short circuits that result in costly restoration.

After the repairs, mice may go back to work and cause the same problem again, unless you take steps to prevent them.

Mechanics See Engines Destroyed by Rodents

"Apparently they have nothing but time," says Rick LeDuc of Rick's Automotive Service in Mariposa, California. He has found elaborate nests in intake manifolds and even litters of tiny pink mice inside air cleaners stuffed with bedding material.

In one of the more ambitious nests, he found part of a broom handle that had been dragged into the inner workings, as well as "a couple of pounds of dog food." In another instance, he said that only the wires coated with blue plastic insulation had been gnawed.

"They are supposedly color-blind, but sometimes they pick out one certain color of wire to chew," he says. "Probably there's something about the taste or texture."

Several auto repair businesses report multiple incidents of rodent damage each month. The time of year doesn't seem to matter. Hoarding, nest building, and wire gnawing are year-round occupations.

Repair costs can be as high as $500 and sometimes much more. In at least one case, so much wiring damage was done that the car was not worth fixing.

City Mouse, Country Mouse

Rural car owners sometimes come into a repair shop complaining that they "smell something burning.” Such an odor may come from smoldering grass or pine needles tightly packed into a carefully fabricated nest, or from burning droppings, stashed food, pack-ratted items, or the deceased bodies of the actual culprits.

A lot of people are surprised to discover the source of their problems. Why are so many furry occupants living where they are not welcome? This is not their natural habitat. Are they planning to take over the planet by disabling our vehicles?

The real reason rodents seek a home under a hood is that it provides a dark, warm, secure place to hide . . . at least until the ignition key is turned. The start-up of the car’s machinery can be deadly for the critters, and sometimes can cause serious consequences for the drivers as well.

An acorn, rolling into a crevice after a driver stepped on the gas pedal, can keep the throttle open. The driver of a late model Ford truck was taken for a wild ride on a winding country road, and severely damaged his brakes before he could shut off the power.

The wood rat culprit apparently abandoned ship before the adventure, but his hoard of nuts almost caused a real disaster. The truck required towing and lots of professional attention.

Collecting and Nesting Behavior of Wood Rats

John Muir, the famous Yosemite naturalist, called the wood rat (or pack rat) "a handsome, interesting animal". In his detailed descriptions of Sierra flora and fauna, Muir also opined that "no rat or squirrel has so innocent a look, is so easily approached, or expresses such confidence in one's good intentions."

The comments of today's vehicle owners plagued by rodent motor damage are much less complimentary -- and are often unprintable. It may have been easier for the poetic naturalist to appreciate the animal, since he usually traveled on foot, rather than by SUV.

Wood rats are notorious for accessorizing their nests with things they collect, ranging from natural curiosities like bones, cones, and stones, to the tools, trash and treasures furnished by humans. Muir recorded incidents of rats stealing combs, nails, tin cups, eating utensils, and spectacles, which he supposed were used to strengthen rat nests.

Once inside an engine compartment, the rats see a mother lode of wonderful man-made objects, with wires and hoses and tubes connected to a spectacular variety of shiny metal and plastic components. To this assemblage, they will add their acorns, pine needles, hardware items, bottle caps, and whatever ornaments suit their eclectic decorating style.

Even before the era of motorized vehicles, settlers contended with these tiny terrors, doing their best to keep rats and mice out of their houses and barns.

Hard rock miners, however, actually encouraged rats to inhabit the mine tunnels, by saving crusts and crumbs of bread for them. The rats acted as a low-tech safety system. Being ultra-sensitive to tremors or quakes, they provided early warning of impending collapses or cave-ins. If rats suddenly went running for the exit, the mine workers were right behind them.

This may give us a clue that a deterrent that causes vibration or sound waves, may be a good choice.

One deterrent that is often reported to be effective, is the use of an electronic rodent repeller such as MouseBlocker.

The low-voltage devices run on your car battery and are easy to install. They emit an ultrasonic frequency heard by rodents, not people. Some of them also activate flashing lights. Another advantage of such products is that you do not have to deal with poisons or messy cleanup of traps.

. . . Lurking everywhere.

. . . Lurking everywhere.

Tape It Up

One of the newest products addressing the wire-chewing problem is Honda Motor Tape. It is infused with pepper and perhaps some other deterrent and is used to wrap the wire harness. Early reports say it works well. It is not cheap, but it costs much less than replacing an entire electrical system in your vehicle.

Some Less Serious Ways to Discourage Them

So are there other ways that pesky little wire nibblers and insulation grabbers be discouraged? Could a car be disguised with animal pelts, to make it look like a rat-eating predator?

Would a ground squirrel be tricked into thinking your car was a mountain lion or a giant badger with the help of a spectacular paint job? Or perhaps one of those big plastic owls could be stuck under the hood and wired it up with a speaker playing annoying rap music.

Some people park their car over a bucket of mothballs, which is apparently repugnant to rat olfactory receptors.

The family dog or cat may help to keep mouselike pests away, though if the cat gets into an engine, it's bad for everyone—usually worst for the cat.

There are also little buzzer things that are supposed to keep pets off the furniture. They might work.

The problem is not going away, so drivers might be wise to pay a little extra attention next time they notice an unfamiliar squeak in their vehicle.

They are out there.

Some of them know where you park your car.

Anecdotal Results of Dozens of Strategies

Realistically, getting rid of rats may be a lengthy project, requiring multiple strategies. Every situation is different. I have hundreds of anecdotes in over 270 comments sprinkled with suggestions, and you can read them all, or read my new article summarizing them, "Getting Rid of Rats or Mice in Your Vehicle: Reader Suggestions."

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

Questions & Answers

Question: The dryer sheets do not work. The rats just made a nest with them in my car. I had eight baby rats to deal with, not to mention chewed up wires. Do you have any other suggestions on how to keep these critters out?

Answer: I suggest that you look through the other suggestions and try two or three of them at the same time. Traps or another deterrent might work.

Question: How do mice get into the ventilation system of a car?

Answer: I think a mouse can get in anywhere. The bigger question is how to get them out. It may require a combination of methods.

Question: What if I filled a nylon stocking with mothballs and wrapped it around the tires? Would this help keep rodents away?

Answer: It’s worth a try. It depends on the situation, but I would always recommend using at least two methods.

Question: Where in a car's engine do you put dryer sheets to keep mice away?

Answer: Most people pin dryer sheets near to the insulation under the hood. Make sure they are not hanging down into the engine. However, this may be one of the less successful strategies, and the sheets need to be replaced often. If possible I would suggest you try one of the electronic devices or traps. It seems that what works for one person may not have any effect for someone else.

Question: Would ground Irish Spring soap help deter rodents?

Answer: Some people have reported that it works for them, others have said it doesn't. It may depend upon the kind of rodents you have. I would recommend using two or three methods

Question: Which type of Irish spring soap works best to keep rats out of a car engine and how long will it last before replacing it with a new one?

Answer: Stick with the original scent. If the fragrance is fading, it should probably be replaced.

Question: I found this white cotton like insulation substances and twig like bunches under that inside under top cover of my engine where I check my oil I've only had this 2015 KIA for less than 4 months. At first I thought it came with the car for extra insulation, but then I thought someone hates me and planted it there. Etc. I never thought rodents could've there. I drive at least once a day. What is this?

Answer: It’s hard to identify the culprit without more clues, but it sounds like nesting material. I would get rid of the material and then put some of the suggested deterrents in place before any damage occurs.

Question: How often do I have to spray the tires and engine with Pine-Sol?

Answer: If you can't smell it, it is probably time to reapply.

Question: Have you heard of the RatMat?

Answer: I had not heard of it, but always glad to hear of a new suggestion. I would encourage people to look it up and to share experiences if you have used it.

Question: What about opening the hood and shining a bright light into the engine all night?

Answer: That seems to work for some. You might want to also employ a secondary method like traps or strong smelling substances like peppermint oil.

© 2008 Rochelle Frank


Rochelle Frank (author) from California Gold Country on June 03, 2020:

Thank you for your comment. It confirms the experience of many others.

Matt39 on June 03, 2020:

We too have been using the Mouse Blocker PRO model that our dealer installed and it has been a lifesaver, will never own a vehicle without one. The repairs are too costly on these newer vehicles to even risk not being protected. We also have one on our lawn tractor as well. When you have mice on your property, you have mouse problems.

Rochelle Frank (author) from California Gold Country on June 02, 2020:

Glad to hear of your positive experiences.

Arial.D.Bitch ( Yes thats my name ) on May 31, 2020:

I saw that some people mentioned their concern about using the electronic devices around their dogs and other pets. We have been using the Mouse blocker device our mechanic suggested for years with great success. Our dog rides in the truck with us all the time without problem. The sounds this unit emits stay inside the engine area our mechanic said and that we should not be concerned. The device has been a life saver for us as the repair bills were getting ridiculous and the constant question "is the truck going to start" was haunting

Rochelle Frank (author) from California Gold Country on May 13, 2020:

That's a hard situation to deal with. For some reason critters seem to be especially attracted to Honda. Some people think it ight be the soy-based covering they use on the wiring. Others think that the design of the car has certain openings underneath that allow animals to get in. Raccoons are usually pretty big. I'm surprised that one managed to get into your car.

Phillip Benedict on May 13, 2020:

I am presently waiting for Honda to finish rewiring my CRV. A raccoon got into it and so far has caused $3000.00 worth of damage. The main harness under the hood clear back to the wiring at my taillights.

Rochelle Frank (author) from California Gold Country on February 26, 2020:

Thanks for adding your suggestion. Anything that hints at regular activity in and around your car--even if it is a device rather than a person--can often be helpful. Certainly worth trying since it worked for you. Congratulations!

DeviceGuru on February 26, 2020:

An LED light bulb (standard style but just 7W consumption) at the end of an extension cord, controlled by a timer, in the engine compartment with the hood raised about 10 inches by a plastic cylinder, has eliminated the rat incursions in our Chevy Bolt EV.

Rochelle Frank (author) from California Gold Country on December 17, 2019:

Some people have reported good results with peppermint oil, however you must remember to apply it frequently since the smell dissipates after a day or two. If you can't smell it, the rodents can't either.

Greg on December 16, 2019:

I’ve heard peppermint oil works in a spray bottle diluted works?

Rochelle Frank (author) from California Gold Country on October 30, 2019:

It depends on the construction of the car. If there are holes or gaps large enough for a rodent’s head,it can squeeze through. If you see openings, it might be a good idea to block them safely.

Rahul on October 30, 2019:

Can rat enter into A-Pillar and chew the wires?

Jocelyn on August 21, 2019:

my car. The stereo syetem along with rhe radio and cd player isnt working. They came through the trunk to the back seat and left a huge hole in my back seat. Chewed the harness on my Grandsons.carseat...the brakes and steering are not right. I am scared to see what the mechanic might see.

Rochelle Frank (author) from California Gold Country on April 17, 2019:

Some people think the soap works, others have seen no effect. Again, it seems that no one thing works for everyone. Multiple defenses are always recommended.

guest on April 15, 2019:

Just spoke to a guy in line behind me at the grocery store, he said he puts bars of Irish Spring all along the baseboards of his garage to keep them out.

I am doing both mothballs in a nylon sock under the hood (till I know for sure they are not coming back) I also have bars of Irish Spring soap in strategic locations.

Maria W Ferrell on April 11, 2019:

The engine light is on in my car and the check coolant light keeps coming on. After it was checked, my friend who is a mechanic said that he noticed that mice had been chewing the wires in under the hood and that may also be why the engine light is still own. He advised me to park the benz outside the house until we can clean out the garage. I hate to see this car which has been in the garage a long time, parked out side, gathering pollen. What can I do?

Marilynn Fuller on April 04, 2019:

My 2011 Hyundai Accent was running roughly, and then the "check engine" light came on. Two out of the 4 cylinders were misfiring because a rat had chewed the wires and shorted out 2 ignition coils. It cost $400 to fix the damage. Today I bought moth balls and pepper spray, and tomorrow I'm buying PineSol and Irish Spring Soap. I also plan to leave the hood up during good weather. I refuse to let those little pea-brained critters win this war!

Rochelle Frank (author) from California Gold Country on February 24, 2019:

Yes, you have to be a little obsessive if you have already had the damage. I think you will find that you can obsess a little less as time goes by, but keep up the good work. You may eventually find that the electronic devices are worth the cost, which is minimal compared to repairs.

Ally on February 22, 2019:

I just spent $1,000 on replacing motor on my steering as the mice, we assume, chewed through wires and other wires near by.

I have obsessively placed mothballs under car, in a sock over night inside engine, peppermint oil on tires and rubber snakes.

I can not afford another chew through. It's exhausting always trying to remember to go out and set up the car at night.

I believe so far so good.

KJ on February 07, 2019:

I stuffed a stiff piece of a vinyl mattress cover in the engine compartment overnight for several nights, tucking the edges into the space between the engine and the compartment walls. The critter could not reach his favorite place on the intake manifold and has apparently found another spot to eat his dog poop and acorns.

guest on February 03, 2019:

The mothballs work but they are disgusting. Remove them before you start your car. Replace by nightfall.

I also put them in my shed (in a nylon sock) and have seen no mice activity this year.

I asked the mechanic at the dealer I go to for maintenance about electronic devices and he advised against.

In his experience they don't work.

I'm hoping I can lighten up on the mothballs this spring, and just use Irish Spring soap. We'll see.

Ellie on January 25, 2019:

Tonight, I was ysing the wifi of a store while in my car. The windows were down about 7 inches. I heard a noise in the backseat near the passenger window, but I thought it was the wind. A few minutes later I heard it again. About ten minutes later, there was crunching coming from the vicinity of the glove box. I turned off any noise in the car and listened again. It was definitely a rodent! The darnrd thing came in the car while I was sitting right there!!! I checked the glove box with trepidation and sure enough, in the empty and just cleaned recepticle were 2 small rodent poops. I got my cane, 2 flashlights, and turned the car on with the heat on high. I ran it while I checked under the hood and banged my cane around. No sign of damage or feces. I took everything out of the front seat, banged the cane around some more under the dash and in the glove box. No leaping guests. After about 20 minutes of this, I turned the car off and sat quietly to listen. No more crunching in the dash. Tomorrow, the peppermint oil, mothballs, etc., are going under the hood, in my glove box and the reaches behind it. I just replaced my cabin filter 3 days ago and I will be mad as heck if that beastie chewed it up!

Rochelle Frank (author) from California Gold Country on November 26, 2018:

It's good that you are taking precautions with the mothballs. Some people have reported success with them.

If you are still seeing evidence of rodents, you might consider the advantages of the electronic devices.

guest on November 08, 2018:

I am back to putting the moth balls in a nylon sock under the hood when the car is not in use (mostly overnight).

I remove the mothballs and put them is a safe place when the car is being used.

I don't want the mothballs to get into the wrong hands, such as children or pets.

I think they are a good deterrent and I believe wildlife knows not to eat them (I hope).

Rochelle Frank (author) from California Gold Country on November 05, 2018:

Thanks for the suggestions. Sounds like it could be effective. Please keep us updated.

guest on November 05, 2018:

On second thought, I have decided to just put the coffee can with the mothballs under the front of the car at night.

Cover the can during the day. Wish me luck!

guest on November 05, 2018:

"Has anyone had success with peppermint oil... i'm reluctant to try mothballs as one can imagine the source of heat / air in your cabin is directly related to the engine during use".

The peppermint and all the other natural stuff may work as a deterrent, however, you have to reapply it at least once a month and it is pricey.

So far I am having good results with the mothballs. I now have them in a coffee can under the hood. Before I start the car I remove them and put the cover on, then a brick on top so it won't blow away.

When I park the car for the night the mothball can goes back under the hood with cover off.

It's a bit of an inconvenience but at about $3 a month it's better than $2000 at the dealers.

If I don't return with an update that means this method is still working for me.

Matt39 on November 04, 2018:

I saw that some people mentioned their concern about using the electronic devices around their dogs and other pets. We have been using the Mouse blocker device our mechanic suggested for years with great success. Our dog rides in the truck with us all the time without problem. The sounds this unit emits stay inside the engine area our mechanic said and that we should not be concerned. The device has been a life saver for us as the repair bills were getting ridiculous and the constant question "is the truck going to start" was haunting. Here is a link to what we are using. https://www.youtube.com/channel/UCQn3ICb6OhwbN6Ljk...

jeff on November 03, 2018:

I created my own problem, I went with step one leave the hood up. The Porsche under the porch and its acorn stuffed crevices were the haven of choice until i exposed it to the elements. These actions caused the migrant caravan of dwellers to seek shelter in the warmth of the Pontiac Grand Am, my daily driver. Its a non permanent residence but they've stopped to chew and redecorate, on what looks like several weekend getaways. Adorning my engine compartment with dryer sheets, to me seems like i'm adding additional bedding components like blankets for them to use. Has anyone had success with peppermint oil... i'm reluctant to try mothballs as one can imagine the source of heat / air in your cabin is directly related to the engine during use.

Rochelle Frank (author) from California Gold Country on November 03, 2018:

I would contact the people who make the electronic gadgets and ask them about the affect on pets. I know some of them use flashing lights, light static charges and/or vibration. Others may use high frequency sonics, but those may be brief or localized. It is work investigating.

Mothballs can be toxic to pets as well. I agree that they are unpleasant.

guest on November 03, 2018:

I forgot to mention that I cannot do the electronic repellants.

I have dogs, surely it would bother their ears.

guest on November 03, 2018:

I found a ginormous mouse nest under the hood of my car about a month ago.

I tore out the hood insulation where the primary nest was and a mechanic helped me with the rest. He charged me a fortune and did not do a thorough job.

Anyway, the dead mouse smell is fading, I have air fresheners in the car and mothballs in a nylon sock taped under the hood.

The mothball smell makes me sick it is prominent when the car heats up.

How long do I have to keep the mothballs there? I drive the car everyday and keep a clean car, no food/clutter. I don't understand why this happened.

Rochelle Frank (author) from California Gold Country on November 01, 2018:

I am hearing from more people who are finding the electronic rodent deterrents are working best. Maybe you need to try another approach. At least the mouse nests smell better.

CDV on November 01, 2018:

I put dryer sheets in the engine and the rats used them to make a nest.

Ashish Bamania on October 17, 2018:

I show a rat in trunk of my car and hour and I'm furious.I can't stop thinking about what it can do to my car. I think I have to get it check tomorrow.

Rochelle Frank (author) from California Gold Country on August 30, 2018:

Check out some of the suggestions. I hope you will find some good ways to help you keep them away.

Christel Jurgensen on August 30, 2018:

New Evoque. Two weeks ago battery wires

eaten, now brake system gone. Live in the Country in Spain and am desperate because obviously not on guarantee.

Sharon on August 22, 2018:

Bought a new 2018 soul kia..n just discovered nest under hood!! 4400 worth of damages! Only have car 6 weeks and so upset over this!!.i guess i will have to try some of these ideas to prevent it from hsppening again n check under my hood daily!!

Rochelle Frank (author) from California Gold Country on April 16, 2018:

Very glad to hear your success story. I hope others will have a similar outcome.

Matt39 on April 16, 2018:

This has been an ongoing problem for us and that is when we found this Hub. So much great information. We chose the Mouse Blocker PRO, one for my truck and the other for my wifes car. Just wanted to share that it has been over a year now and we have not had any mice return to these vehicles.

Reading through all the comments there are so many people frustrated with the problem, I figured I would help a bit with the solution we found to work.

Rochelle Frank (author) from California Gold Country on April 16, 2018:

Yes, it can happen anywhere. You need to do some preventive work or they will return.

Steve M on April 16, 2018:

I don't live in the country (Liverpool) but have just found my 2018 skoda octavia has been home to rodents. they chewed the loom and the plastic casings off the battery. i use the car every day. the cra was fine Saturday but the errors showed on Sunday. the damage was discovered today (Monday). fast workers. there is bread and dropping all in the nooks and crannies.

Rochelle Frank (author) from California Gold Country on April 04, 2018:

I hope someone else will answer this from their own experience.

I think spraying in on the hood insulation, and in the interior might be the best places. That being said, I ‘m not sure peppermint is the best deterrent. It might help,but it will need to be reapplied regularly.

Bellisima on April 04, 2018:

So if I am to try the peppermint oil approach, where do I place the oil? Directly on the engine? I have a new Kia Optima Hybrid and certainly do not want any problems. I live in the country and due to lots of work being done in the area, the rats are out of control.

Thanks for your help..

Rochelle Frank (author) from California Gold Country on March 25, 2018:

@Ed. Buying a different vehicle may not solve your rodent problem. Yo probably should put some deterrents in place. The electronic devices might cost you between $60 and $80 or so, but its far less than the repair bills you could have.

Ed on March 25, 2018:

My new 4runner, that I drove every day, had the wiring harness and the filter eaten by rodents. I had Toyota buy the vehicle back...

Esther M on March 12, 2018:

We were proud to purchase a Mercedes SUV for a very good price. Sadly, not even a month after we ended up spending a total of $4000 in repairs due to rat damage. We are fighting those things to the core!

vic on March 09, 2018:

So the possums and mice started to get in my car , I fixed that I rigged wires around areas that they were getting into , the wires are hooked to and electric fence ticker , the possums don't go anywhere near my car anymore , surprise wonder why ?

Rochelle Frank (author) from California Gold Country on January 25, 2018:

We are both Californians, so I understand.

Kenna McHugh from Northern California on January 25, 2018:

LOL! I meant proximity of the river. I wasn't thinking about the other rats close by.

Rochelle Frank (author) from California Gold Country on January 25, 2018:

Thank you Kenna. Were you referring to the proximity of the river or of the State Capitol politicos?

Kenna McHugh from Northern California on January 25, 2018:

What an informative article. It caught my attention because I had a friend who was out $1500 because rat or rats were sleeping under his Toyota's hood at night. That was the first time I heard about it. He lives near the Sacramento River, which explains the rats being nearby.

Rochelle Frank (author) from California Gold Country on January 25, 2018:

They are tricky little critters. If that was the extent of the damage, you got off lucky. You should probably use some of the suggested deterrents to be safe.

Dawn on January 11, 2018:

I have a 2013 Ford Explorer Sport that suddenly started raining washer fluid on me through the front dome light when I used the rear wiper with washer. Brought it in, they looked inside the headliner pulled out a bunch of the insulation the mouse used to make a nest. Somehow it got in through the engine and crawled up inside the window frame. First time they saw this happen.

Derrick on December 21, 2017:

I've got rats chewing on all hard plastic surfaces under the bonnet of my Toyota Prado, but so far not the wiring. They have destroyed the windscreen wash bottle and left teeth marks everywhere. The vehicle is parked in my drive. I often leave it in the bush (I'm in Australia) and thought that bush rats were the culprits. No longer, I think it is rattus rattus. I'm trying a motion-activated light.

Edward on December 07, 2017:

I took my 2016 Toyota Prius in for the routine 30,000 mile service and they found rodent damage in the AC system. They are repairing it at a cost of $5,300. Some mice carry the Hantavirus which can be deadly to humans. So I was apparently breathing their feces and urine. This is an important health issue and should be addressed by removing soy and cornstarch from "plastic" including wiring insulation.

Rochelle Frank (author) from California Gold Country on November 30, 2017:

Poisons are also very dangerous to other animals that eat rodents, including domestic pets - dogs and cats. Improper handling or storage of them can endanger humans too.

L Tanner on November 30, 2017:

As I have read through comments I see lots of mention of "poisons". Please do not do this. When you feed a rodent poison, they get thirsty and go for water. Birds of prey and snakes then feed on poisoned rodents and die. Please do not use baits and poisons. Set mechanical traps with peanut butter. Please.

L Tanner on November 30, 2017:

I have battled mice in my engine and air ventilation system for over a year in my two vehicles, a Honda and a Nissan. I wasted money on two ultrasound devices; I may as well have piled up my money and set a match to it. I used Bounce dryer sheets and peppermint oil. After every new fix the next mouse nest was more robust than ever. I have read that mice travel in pairs, so a single trap will not suffice. I bought the traps where the door shuts and they are very effective, but expensive since you throw the device anyway. The only upside to these traps is you don't see the mouse. I believe that I may have solved my problem, at least for the time being. I purchased several sets of the Tomcat white plastic reusable traps with the large white teeth. You bait the well with peanut butter, set the trap, and place it inside the car engine compartments. If you can find room, set two as close together as possible since mice travel in pairs. Be sure to put a sticky warning label on your steering wheel so no one drives the car without removing the traps first. The first couple of nights I put traps on top of the front car tires and caught mice in each. Disposal is easy, put on plastic gloves, throw the mouse away and wash the trap in hot, soapy water with a drop of clorox, and rinse well.

The other thing I discovered was that the mice were getting in the insulation on the underside of the car hood. They were transporting this insulation into the ventilation fan area behind the glove compartment, mixed with leaves and other junk. I replaced the insulation and then sealed the cover with duct tape.

The thing that I can't stress enough is the importance of cleaning the ventilation system as much as possible. The filters are really expensive, even online. But if you find that your in-cabin air filter has been contaminated with rodent droppings and urine, you must replace the filter. Mice carry Hantavirus and other serious disease organisms. When you are removing mice nests and doing the cleanup, wear a mask and plastic gloves. Be prepared to completely clean your vacuum cleaner if you use that to vacuum out the ventilation system. There are commercial disinfectants to spray in your car's air intake, but Lysol spray works as well.

I have been dismayed by the flippant attitude shown at my Honda dealer's service department. I get the feeling that they don't care in the least. The money they are raking in on car repairs caused by rodents is substantial.

Rochelle Frank (author) from California Gold Country on November 19, 2017:

More and more people are blaming those soy- based wire coverings and it does seem that vehicles using those are hit the hardest, even though other cars suffer the same fate. It sounds as if you are doing your best by using a multi-faced strategy. When they replace the wiring do they use the same materials? It is terrible to have so much damage done. Hope the lights work, but I wouldn't stop the other strategies.

aj burg on November 19, 2017:

Had a rodent get into my 2014 Hyundai Sonata about a year ago doing considerable damage to the electrical harness under the firewall and up and around the steering column. Also, considerable damage was done to the rear back seat, trunk covers and a hard piece of plastic.

I took it to the Hyundai dealer where I bought the car to have the damage repaired at a cost of over five thousands


Well guess what!! Something got into the car again last week and again overnight today digging holes throughout the trunk and back set-three times in four days.

After the first attack last week I went to Home Depot to get the large RAT TRAP stick pads ,poison pellets and heavy duty rat traps ,traps that can break a finger or worse.

I placed the pads inside the car on the floor in front of the front and rears seats .I also placed the heavy traps in the front and rear .I placed moth balls stuffed socks in the hole in the top rear seat hole they made last week.

As far as the trunk I placed a moth ball stuffed sock into the hole , arranged a large number of the adhesive traps , spread poison pelts across the entire trunk floor and set the heavy duty rat traps. WELL GUESS WHAT. THEY GOT IN AGAIN OVER NIGHT. DOING MORE DAMAGE.

One auto body shop indicate after viewing the damage indicate that it was getting into the vehicle from behind the rear wheels, but not fully sure.

I was told that the soy based cable coverings are the cause for attracting the rodents, This environmental BS, if the cause, must and should be covered by covered by Hyundai.

Note: all of my other cars -older Chevys, Oldsmobile, rental cars,for years were parked in the same area with no problems. I had a 1977 Chevy Nova Classic parked in the same area for years with no problems. Only this Hyundai.


I will place some large lights into the car tonight that are motion activated.- one under the hood, one in the trunk and another in the front and back seats at a cost $ 160.00.

Rochelle Frank (author) from California Gold Country on September 19, 2017:

I can understand your frustration. They do not give up easily. Have you tried the electronic devices?

Let us know if you find something that works for you.

Lyle on September 19, 2017:

Just got an estimate for over $1,000 for our Honda S2000 with rat damage. Have Irish Spring, Pepper Spray, Pinesol, Moth Balls, Ridarat lights in addition to a special drop light running from our electrical outlet and they still got to it. Nothing really works, but might be a deterrent in some areas. Good luck everyone!

Lynn on September 10, 2017:

They took the cotton balls filled with peppermint oil into the spare tire area where they were building a very large nest. I don't know where they got some of the stuff I found in there.

Under the hood they ate on the Irish Spring soap, 1 small piece remained with chew marks on it. I hope it made them sick

I can't figure out how they got inside the car.

I was using Rodent Sheriff under the hood on the hood insulation regularly about every 2 weeks for about 9 months and they never bothered it even through the winter. But I let it go for a few months and now it it has been chewed all over it. about half of the cover is completely missing.

Now I'm using Cab Fresh inside the car and in the trunk, 2 in the trunk & 2 inside. They need to be replaced about every 2 months. I'm not sure if they are still visiting because I'm not leaving anything they liked before like tissues and paper. But, I think I'll put a tissue in just to see if it's shredded. They chewed a hand-towel I had in the car once, it was shredded. They haven't bothered a map on the backseat.

The gas line to our van was chewed 8 times over the last few years and had to be completely replaced. The mechanic couldn't tell if it was a mouse or squirrel.

Living in the woods is no fun. I also have a few squirrels that are driving me crazy. When I see one playing mechanic I hit the horn from inside the house. He runs and stays away for awhile, the other one doesn't budge. We tried to trap them with peanut butter and peanuts, but they won't go anywhere near the trap, they look at it but walk way around it.

I don't think it helps that the neighbors have horses.

I have come to the conclusion that it's time to move. I guess they win.

Steam on August 14, 2017:

I thought I would have this issue licked before it got started. Living on farmland and having a large carport/ open shed away from our house where we occasionally park a vehicle. I knew the presence of field mice. It has always been a concern as once they did make a nest inside a garden tractor. No damage so I just cleaned it out. Put my trust in our shed night watchmen, the black snakes who love mice. And just as an added precaution I always spread rodent poison pellets behind the walls and around to keep em in check. Parked our Audi A4 there for a couple months and then began to drive it when we got a check engine light and then a foul smell, something like mouse p and something dead. Long story short, mechanic found poison pellets inside the air pump, air filter, and cabin air filter, along with a dead mouse. I remember a story a guy told me about his travel trailer where the mice gathered the poison he had spread around to eliminate them and they carried off and distributed the stuff to other hiding places in the unit. I guess a more tasty, lethal poison may do the trick if something like that is available.

katrina on June 27, 2017:

i drove my car yesterday and everything was fine. I jumped in my car this morning and it stunk so mad and noticed they chewed a shit load of interior, back seat belts, my daughters car seat belt and many other random items. they had a full buffet for diner last night and my daughters toys for dessert all in one night. oh and also chewed my back seat sooo not happy. I live right next to a creek. little fudgers are gona die tonight

Whatever works on May 16, 2017:

Cover the engine with fitted a sheet of metal mesh so they can not get to the insulation under the hood and tear it up for nesting material. It is safe to drive with it in there.

Use glue traps and snap traps with peanut butter.

Check under your hood every single day. Check all shrubbery to look for nests in your yard. If you cant see light coming thru thru the bush/tree etc, because of a nest -it could very well be a be a rat's nest.

Rat nests can be found on the ground as well as up in the trees. Destroy them completely.

Dogs/cats are an excellent deterrent to rats.

Bob Tanem -the gardener-has a recipe to kill rats suing plaster of paris.

Look for entry holes into your house, especially on the roof.

Tim Delaney on April 28, 2017:

Wow! I've had rodent issues on 4 cars, including my new, 2017 Forester, where a little bugger was chewing at the insulation on the firewall, and recently had a check engine light on my 2005 Mercedes C240. I had it in the shop today and a critter got into an area near the gas tank, made a nest which jammed a solenoid open, tripping a trouble code on the computer. This can be real trouble: dead or damaged vehicle, including a real chance of a fire. Thank you for your article – as you point out, it isn't a panacea, but it's a great place to start.

Debbie Back on April 28, 2017:

I had this happen about a month ago. $150 to repair my 2012 Dodge Ram truck. We live in the country and just about all of the suggestions above are not possible. The mechanic advised us to spray peppermint oil mix all of the inside of the engine. We did that. Last week my engine light came on again. Took it in today and again rat damage.

Paul Chippendale on April 20, 2017:

I just had the same problem as one of your contributors. A rat had eaten a large proportion of the rubber tube of the windscreen washer, replaced it yesterday, the rat has now eaten through further down where I can't reach it. I need to get to the washer bottle,thank you Nissan for putting it in such an inaccessible place, I've only got to take the front wing off!

Bob Mayo on April 19, 2017:

I tried many things. Unfortunately (for the critters), the only thing that really works, and that I now continue to use, is a pellet rifle I bought for less than $100 -- a lot less than the $500 I spent to fix the cables the last time.

Penny Garzarek on April 04, 2017:

Some sort of critter is wreaking havoc on my truck tires. ONLY my 3/4 T truck - not my SUV or a smaller truck. Seem to particularly love the right passenger tire. Have spent about $2K in replacement tires - another one ripped this AM on the outside so cannot be fixed! It appears that whatever is doing this extremely costly and maddening damage has a sharp, probably pointed tooth that it stuck into the tire and then pulled across and leaves about an inch or so long tear that resembles a pencil line. Usually more than one place. WHAT is doing this and what can we do? We've tried wolf urine, critter repellant spray for vehicles, have built wooden covers that they can apparently get under. I'm broke and so upset at this point. We have a camera to use if I can get it set up - not very technical, but have called a friend for assistance. Anyone???? Thanks --pls email BGarzarek@aol.com.

Rochelle Frank (author) from California Gold Country on March 26, 2017:

Some people have reported that Irish Spring soap or peppermint oil is helpful as a deterrent. Others have said they didn't help much. I have not heard of using peppermint candy. It doesn't seem that it would be a strong enough mint smell, but if it works for you, go with it. Since you have some proven success with the traps, I would keep using those as well.

crickett on March 25, 2017:

last 2 days i have caught 2 mice in the trunk of my car, with tomcat mouse ytraps. just started seeing mice droppings n my car. since i use peppermint candy in my house in my kitchen drawers 3 months ago ,i have not seen any mice droppings at all, so i am gonna put in my car. i have heard of irish spring soap working, just might add that also.

Howard Alameda on February 09, 2017:

Just wanted to know if any one knows where the hole or if they had this problem I guess I have to lift car up and look under 2002 pt

c ruser

Palsekar on January 31, 2017:

When I started my new car which was parked for three weeks, it displayed indicators along with a message 'Check Brake System' on the dashboard monitor. Car has to be towed to the service center because it didn't let me release the hand brake! Reason: Rat/Rodent bit of wires inside the hood costing me hundreds of dollars :(

Janiebtrue on January 16, 2017:

Ok, the mechanic found a mouse nest under the hood of my car. (didn't even know mice made nests)

I live on 5 acres. My car is parked under a carport.

This may sound like a ridiculous question but can can you strategically place the dryer sheets under the hood so you can drive the car with the dryer sheets under the hood? And replace them once a week?

...or are all these methods for when you are storing a car.

I drive my car almost everyday and can't imagine I'll have to open and close the hood every time I leave or come home to remove and replace dryer sheets! Help???

Elimann81 on January 14, 2017:

When our son was living with us(on 80 acres) he drove in after work but the next day his car would not start. Popped the hood and there was a mouse nest. What to do


Rochelle Frank (author) from California Gold Country on January 02, 2017:

Sounds like a lot of work. I have heard of people making these kinds of fences,and making sure their vehicle is always properly enclosed. If it works, it is certainly worth the effort. Thanks for your suggestion!

Help. on January 02, 2017:

I took a roll of 18in roof flashing and stood it on its edge,with stakes, and went around a vehicle to stop these pests. It is too high and too slick for them to get over. If they dig under just make a trench to set the flashing in.

Rochelle Frank (author) from California Gold Country on June 24, 2016:

Yes , I think it is still an ongoing problem for many people. I'm happy you found something that works for you.

Matt39 on June 24, 2016:

It crazy how this thread keeps going. Wanted to update everyone that the Mouse Blocker we had installed 2 years ago is still protecting us today. We thank our mechanic every time our vehicle is in for service he and tells us he has saved 100's of cars with this unit. What an amazing device this has proven to be. Just wanted to share our success story and hopefully help others with this same issue.

Rochelle Frank (author) from California Gold Country on April 25, 2016:

Sounds like a good idea, If it is working for you, others may want to try it.

hemanth Kumar G on April 22, 2016:

best solution i have found successful is used coil springs wound on the electrical wires. Yesterday i found fuel pipe is chewed, again i used the same technique and found it is safe.

Rochelle Frank (author) from California Gold Country on April 12, 2016:

It's amazing what they can do.

Parking in another place may help, but using some of the other suggestions might be wise as well.

Traps, Peppermint oil, even electronic devices cost much less than $200. Good luck.

Ruthie1225 on April 11, 2016:

We found a fresh nest as big as a person's head on the motor of my Ford Escape. Built out of a pile of clean white fluffy pillow stuffing with a top layer of fresh yellow straw. Don't know where the pillow stuffing came from, but the straw had probably covered spring flowers someone planted too early. Don't see any nearby, though. The critter - whatever it was - also shredded the hood liner and added that to the mess, and it's going to cost me almost $200 to replace. I have to park outside, but I'm parking about 150 feet away for now, to my great inconvenience!

Rochelle Frank (author) from California Gold Country on March 26, 2016:

I think you are right. Auto design is not the main problem, yet it does make you wonder why certain makes seem to this problem more often than others. Thanks for your comment.

Infinitro on March 22, 2016:

I've been working in the auto industry for 30+ years and I've repaired cars with this problem. They just cleared out the field across from me and my wife's GMC had wiring damage yesterday morning. They chased the rodents out of their home to look elsewhere. I AM going to try the mouse blocker and a few other ideas I have read here. I am NOT going to blame the auto industry and blame poor design. We have a rodent problem, not a car problem. Do defective, poorly designed forks make you fat? Do defective, poorly designed pencils misspell words? Come on, you have got to be kidding me with that stuff!

Rochelle Frank (author) from California Gold Country on January 28, 2016:

It looks like the rodents caused a very expensive problem for you. If the repairs are done with the same soy materials won't that set up the same situation? I hope you can find some good deterrents. I have another hub that summarizes the reader suggestions posted here.

Mike Russo from Placentia California on January 23, 2016:

Rochelle: Thanks for posting your article. Here is my story:


Rochelle Frank (author) from California Gold Country on January 04, 2016:

It is very frustrating since you rarely see the culprits before the damage is done. Maybe you can get your mechanic to go to bat for you to help bolster your insurance claim for the additional damage. In the meantime, I hope you can find a way to prevent further damage. Condolences.

Julie on January 04, 2016:

I just had to have all my engine wires replaced in my car from a Rat eating through all of them. Now that the wires are replaced it seems like I have a blown head gasket. My car was in the garage from Thursday evening through Monday morning when I went to work. Oddly my emergency brake light was on. I worked all day and drove home Monday evening and went out to start the car Tuesday morning and it wouldn't start that's when we found all the rat damage . My insurance paid to repair the wiring and now they look like they are gonna deny the blown head gasket.

Rochelle Frank (author) from California Gold Country on May 25, 2015:

Thank you, Please do update with your results-- there are a lot of people who are interested.

Steonghold_grace@yahoo.com on May 25, 2015:

I will surely try all of this to get rid of the pest in my engine....I will update you if it worked!!!

Rochelle Frank (author) from California Gold Country on May 02, 2015:

I can't help -- maybe someone else has a suggestion. Chances are you'll need a mechanic, make sure he knows the details.

Jim Greaves on May 02, 2015:

I just found a mouse nest on the intake manifold side of the air filter in my diesel van (E350), MEANING it must have come through the tail pipe - I guess. The van was running rough, and not accelerating to over 40 without a downhill to help. I removed the nest with 4 "pinkies" in it and the shredded tissue. No sign of mom - I suspect she was sucked in and has clogged the fuel-air injection area... ANY SUGGESTIONS (other than expensive repairs)? Thanks in advance!

Rochelle Frank (author) from California Gold Country on April 26, 2015:

Glad to hear you found a solution.

GeorgeJohn243 on April 24, 2015:

I had rodent accessing my truck when left in the garage while in Arizona. First winter my truck was damaged, next year I tried the home remedies on the Lexus, nothing but gnawing results. The past three years I installed an item called the Rodent Diverter System or R.D.S. for short. Best $49.95 plus shipping & handling I ever spent. Bought it direct from the inventor, he only needs the vehicle tire size. Works on all vehicle axle configurations including aircraft.

Rochelle Frank (author) from California Gold Country on April 24, 2015:

Thanks for the comment, Saharian. It sounds lie you got off pretty easy. Hope the suggestions help prevent additional damage.

Saharian from Wyoming on April 23, 2015:

My mechanic told me that making sure I run my car once a week during the harsh Wyoming winters should solve the problem. I just had to get 6" of wire replaced. I was lucky that the damage wasn't worse. Thanks for the additional ideas to prevent this from happening again!

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