MouseProofing the Prius

We proudly own and drive one of the most reliable and technically advanced cars ever made. A true marvel on wheels. And yet we're vexed by the same four-legged pests that have been bringing disease and death to mankind for thousands of years. . .

On the other hand, I have an uncle who emigrated to Australia decades ago. Down there, they have large, toxic spiders that do the same thing! Me? I'll take a thousand rodents in my Prius over one giant, poisonous fugly spider!!!

 

First time posting. I received a 2012 Prius V from my brother and have loved owning and driving this car, minus the few oddities (wheels skipping when going over bumps, no ability to accelerate out of icy conditions). Today I was following the "sticky" advice to new Prius owners and realized I needed to check out my cabin filter. Found a nice big mouse home, in addition to an incredibly filthy air filter. All that to say, I'm very thankful for this thread and this community. Tons of useful information!

 

You want to take off the windshield wipers and cowl, install some 1/4" mesh over the cabin air intake. The same thing over the air snorkel leading to the engine air filter box would be worthwhile too.

 

The meeces are cute and in my current condition I hate to be mean to them, but I was sittig outside today in the sun and watching a mouse jump from the wheel to the ground several times. Had hubby set six snap traps this evening. Already caught four meeces. Hopefully that is it. And, yes, I already have most -- if not all -- access points screened off.
kris

 

Opps, no more in the snap traps, but found two deer mice in the live trap, which is about five yards from the Prius. Husband will have to let them out down in the forest when he gets home later today. The pair look O.K. They are feasting on a mound of peanut butter.

 

Opps. This is turning out to be one of the worst springs for mice we have had for several years. Each night z we are catching at leat one rodet, and some nights up to four. Must have been our mild winter. Take care, esp. if you are in Oregon.

 

So I skimmed through this thread - but I didn't see anyone mentioning, for instance, adding LED lights into the front hood of the car to be attached to the 12V fusebox, and then another light perhaps attached to the 12V battery in the back.

Look up Loraffe Under Hood Animal Repeller on Amazon which has good reviews, way cheaper version of that mouse blocker device which goes for 3x the price & it has strobe LED lights. Buy two so you can put one in the trunk and one in the front hood. There is also "Exterminators Choice Vehicle Protection Mice & Rodent Repellent Vehicle Wiring|Protects Engine Wiring" which has strong reviews too on Amazon.

This in addition to using dryer sheets, peppermint oil, moth balls, & any chemical repellants, possibly some additional LED strips should do the trick I think in addition to mouseproofing with stainless steel mesh.

Also, it would be great if someone could do a video showing how to thoroughly mouseproof the third gen Prius. It seems fairly straighforward, but a video showing the disassembly of the rear hatch area, and cowl area and then installing the stainless steel meshes would be great. Maybe when one of you get the chance to do this mod on your current or future car, it would be great to post it up on YouTube.

Finally – there is anti rodent insulated repair tape that is on Amazon - does anyone know which cables should be protected given Toyota made everything practically soy based? A guide on which cables/systems should be insulated with mouse tape would be helpful!

 

Detailed Guide On Making Prius Mouse Proof:

So I scoured the PriusChat forum, Reddit, and Google and compiled everything I found relevant to this topic in one easy to find place.

This is a detailed summary of the different things that can be done to protect against mice/rats.You should read the entire thread in here, and also do some google searches to see the different topics on the subject.

The installation doesn't appear to be difficult, and more of a pain in the arse if anything.

1) Use <1/4" galvanized stainless steel mesh i.e. "fine-mesh galvanized hardware cloth and stainless steel self-threading screws" over the entrances to at least reduce the chance of infestation – make sure the mesh is <1/4" - smaller the better as 1/4" (size of a dime) is big enough for a mouse to fit into.

2) The major threats are A. the 2 rear hatch vents; B. 6-7 openings below the cowl of the front hood (below windshield) including the cabin air filter area, and the hood latch area; & finally, C. the engine air filter. The 2 rear hatch vents can either be sealed from the inside which involves removing the side liner, or you can go from the outside and remove the bumper.*

3) When the setup is complete, the primary risk will be your wires in the front hood - so putting LED lighting in there, spray/liquid treatments, anti-rodent tape, am ultrasonic rodent repeller with strobe lights, etc. will reduce odds of infestation even more. I would consider a high frequency sound emitter in the engine bay, AND trunk space (find on amazon - connect to 12V battery in trunk and also the 12V fuse box in the engine; mice/rat repellant chemicals like spray, moth balls, peppermint, scented dryer sheets with variable efficacy; possibly some LED lighting in the front hood area & trunk space (connected to 12V of course).

The first post in this mouse proofing thread covers I think 95-99% of the primary threats for entry for both 2nd & 3rd gen Prius - but you want to protect wires in your front hood area (using probably a combo of LED lighting, rat tape, and rat spray - see on Amazon b/c those are still soy based and significant numbers of Toyota and by extension, Prius owners, have had their electrical systems ruined costing several thousands of dollars - now this is probably unlikely to happen especially using a multifaceted approach above, but the more protection the better.

Here are some links for further required reading to make the Prius resistant to rodent infestation & wire damage:

1) mice &amp; screening off cabin air intake | Page 2 | PriusChat - More pics of the vulnerable areas

2) Diary of a Wimpy DIYer | PriusChat

3) MouseProofing the Prius | Page 4 | PriusChat

4) Toyota claims not aware of mouse problem | PriusChat

5) prius mouse siteriuschat.com - Google Search

6) Mice love our Prius - General Discussion - Car Talk Community

7)

8) Diary of a Wimpy DIYer | PriusChat (Last pic in this post that is showing the front hood hinge: According to hobbit's comments that opening may indeed allow mice to get into the AC system - "All that screening may be for naught as there are still large openings *behind the hood hinges that lead out toward the sides under the front quarter panels. It really needs to be over the [inaccessible, of course] A/C opening itself."). Either of the 2 following solutions can "fix" this:* 1. mouse in car | Page 3 | PriusChat or 2. MouseProofing out moused | PriusChat

9) A poster mentions that in his 2nd gen Prius (2008) - that there was an opening here: MouseProofing the Prius | Page 6 | PriusChat - Not sure if this applies to third gen (2009-2015).

Here's also a summary on the major areas:

1. Cabin Air Filter Screen Fine-mesh galvanized hardware cloth - Diary of a Wimpy DIYer | PriusChat

2. Screening Cabin Ingress Points - great, but only covers each specific ingress points, can't miss any, only excludes access to the cabin area itself, most of engine compartment + mechanicals still exposed).

3. Hatch area (2 vented openings) - What did you do to ur Gen III Prius today???? | Page 205 | PriusChat Note: This is a method that allows you to put the mesh screens on the external side of the 2 rear hatch vents instead of installing it in the inside which can be complicated b/c you have to remove the side liner. Instead, if you remove the bumper, it's very straightforward to install the screen meshes on those 2 rear vents. You can, however, install the screens on the interior side, & links were posted above.

4. Engine air intake (intake funnel, cloth vents)- See: Simple and &quot;cheap&quot; mouse-rat air intake screen... | PriusChat , Any experience/success with blocking and preventing mice | PriusChat . "You have to screen a round hole in the "air resonator," which is a boxy plastic tube that leads into your air cleaner. A mouse can easily enter that hole and neat inside your engine air intake."

"Here is a picture of the 2012 ("Gen III") engine bay (https://attachments.priuschat.com/attachment-files/2016/07/109887_Toyota-Prius-Engine.jpg), and I drew a red circle around the part where the air comes in. You probably have to remove that whole assembly, which is very easy if you have a basic set of ratchets. I circled a second part using a thinner pen, which is a sort of fabric-like material that's on part of the resonator pipe, which mice could chew through. I would just cover the air opening first, and inspect for signs of damage to the fabric-like part.

To be clear, this is how air enters the engine, not the passenger compartment. But Prius owners who've had mouse infestations have had the mice enter through this point and nest inside the engine's air cleaner, which can lead to serious engine damage if they eat through the air filter and then get sucked into your engine when you start it."

"The procedure for removing the wiper arm assembly, which lets you get to the passenger air inlet openings, can be found in the spark plug replacement video in this thread: Nutz About Bolts Prius Maintenance Videos | PriusChat & this video:

. "

5. Engine compartment, firewall (7 openings).

6. Cabin air intake (unknown # openings, possible diffs between Gen II and Gen III?).

7. Odor deterrents - (only a deterrent, can cover engine bay if applied there, odor can get into cabin), mothballs (mixed reports of effectiveness, benzene odor of mothballs fades, seems like you need to break the mothball crystals in order to get it to release more odor after a while), peppermint oil (questionable effectiveness, I've tried these with rodents in homes, never seemed effective, wears off) *WHAT HAS WORKED: scented dryer sheets. Just secure them under the hood in places where they won't be exposed to moving parts or very high temperatures.Change them every 2-3 months.

8. Transtar Amber Rustproofing spray (Rude person's cites using this to prevent corrosion in the engine bay and undercarriage areas and speculated the smell+texture may additionally deter rodents as well): Rustproofing like Krown or NHOU comprising of petroleum oils and waxes would serve the purpose of slowing down rust and repelling mice. Soy based wire insulation is an attractant to rodents. Petroleum based products repel them. See: Mice have invaded | PriusChat and Rust proofing......the added benefit of &quot;mouseproofing&quot; | PriusChat .

"My husband's and my friend recommended to me as he has used rustproofing for over 50 years and never had rodents chew anything in or around a car. My 7 year old Prius v has had no rodent activity. My husband even rustproofed his 2016 Nissan Versa Note.

Rustproofing is cheap insurance, even if there is less rust here in the South. My husband worked on a 2016 Toyota 4runner. Rust has already started to corrode the chassis bolts we removed to do an oil change."

9. Ultrasonic deterrents (only a deterrent, similar to odors with added disadvantage of needing power source, reports of mixed or limited effectiveness, not only for rodents but pests in general such as in homes).

10. Rodent Deterrent Tape/Tubing - (deters chewing on wiring, this tape has capsaicin, citrus, or similar irritants embedded in it in high enough concentration that they really won't like it (products share theme of warning that contact may irritate skin/eyes), do they have to bite it to learn that it tastes terrible?)".

Amazon Items Of Interest:

https://www.amazon.com/Loraffe-Ultrasonic-Automobile.../dp/B07JFXVRMT - One for front hood and one for rear hatch possibly - it is an ultrasonic frequency emitter (humans can't hear it), and it also has strobe lights to deter mice - not entirely sure on efficacy but it's relatively cheap & it has good reviews.

https://www.amazon.com/Exterminators-Choice-Protection-Repellent-Chewing-All/dp/B01DTBOV06/

https://www.amazon.com/Mouse-Blocker-Anti-Rodent-Insulated-Repair/dp/B01FUVTZKY/

https://www.amazon.com/Fresh-Cab-Botanical-Repellent-Pouches/dp/B00L236OMW/

Note: In the fuse box under the hood there is a constant 12V signal coming from the 12V battery that's around the right rear tail light. You could wire 2 of those ultrasonic deterrant devices to the same 12V battery this way & it also has strobe light effect.

Here's another guide that gives a general overview of the mouse problem that's specifically plaguing Toyotas & particularly the Prius: Does your car have soy based wiring? - How to Prevent Rats from Eating Your Car Wires with some additional tips.

Also - if you're going to do a fridge in the Prius, I would store all foods in there – anything that smells in the open can attract rodents - try not to eat in the Prius. Also realize that when the Prius front hood area is warm - that vermin will like to sleep in it for warmth.

 

Holy smokes!

One comment: galvanized regular steel mesh is fine.

 

Isn't that 1/4th" size? Mice can fit into holes at 1/4" diameter.

 

Mesh 1/4" c/c is pretty tight. Very common hardware store item, for bird/rodent intrusion.

You'll see it too, preinstalled in kitchen range and bathroom exhaust vents.

Any tighter and it starts to act as a filter.

 

I've since learned more about rodent exclusion having to deal with removal and exclusion with my family home.

Like most pest creatures, although scents will attract mice and rats (*if* they feel it's safe enough to investigate), it's not just a matter of food. They're also attracted to areas that are warm, dark, and sufficiently enclosed because they're seeking shelter from the elements and predators. This + air leakage from human homes, which is usually heated air, is one major attractant to rodents and other nuisance animals such as raccoons. Often such air leakage will signal to them that there's a potentially safe area for a lair behind and they'll be more motivated to tear past obstruction, particularly to have litters.

So, even if you never leave food laying around the car, they may be attracted enough by a warm engine compartment to investigate, and from there move about to any other accessible area and build nests out of any soft material (insulation of all types is a favorite--the pink insulation in some images and videos appears to be fiberglass insulation but I'm not aware of where in the Prius this insulation is even being used--trim cushioning and soft fluff insulation is white fluff, EPS foam, PU foam, some small amounts of black seemingly viscoelastic foam, and multi-colored composite foam).

As mentioned earlier, exclusion only works on a mostly enclosed with identifiable ingress points. This is the cabin space but neither the engine compartment nor areas under the bumper covers. So a recently used car, parked anywhere where rodents have easy access to, such as many garages, or worst case outdoors near natural cover, e.g. bushes, piles of wood or other materials is high risk exposure.

Shawn Woods from the Mousetrap Mondays youtube channel performed some experiments testing whether mice/rats would eat normal sunflower seeds vs seeds soaked in the spice compound capsaicin (which is what is presumably used in the rodent tapes sold on Amazon), in a couple variations. He found they do technically work, but the capsaicin level needs to be quite high, which is presumably what's in the rodent tape, and it didn't seem to stop the rats from trying at least some of the capsaicin sunflower seeds even though left a good portion of them there. Otoh, there are mixed reviews of these tapes on Amazon with some claiming rodents chewed through the tape all the same, which is somewhat consistent with rodents not being above trying it.

I've had a can of Transtar spray for years now but I've still actually yet to get around even trying it just to get a whiff of what it smells like. (And I still haven't gotten to removing the windshield wiper assembly cowl to screen firewall openings, never having the time. I thus far appear to have been rather lucky coming up on 100k miles without any obvious signs of rodent presence, but I should probably get on that soon..)

 

Guess it's past the time I can edit my post. I should re-state, screening requires screening all points of potential ingress. Can't cover any of them either since their primary functions are providing adequate airflow.

Also, according to the technical data sheet, the Transtar Rustproofing spray is intended as an undercoat (for exposed metal) to prevent rust, and isn't recommended for exposed areas because it remains tacky. That, and/or potentially high VOC content may be why mice don't like it. Without topcoating the rustproofing the tackiness may be why mice don't like it, but leaving it as a top layer may attract a lot of dust and leaves/bugs to stick on its surface? Guess one way to find out is to just test spray it on a small sheet of aluminum flashing and see what happens to it after its cure time..


Amber Rustproofing | Transtar Autobody Technologies

 

I just happen to come across this one today in a shop. Just a little restrictions on the air-conditioning air flow out the blower vents

 

While attempting to loosen the 12V positive terminal bolt under the hood, in the fuse box, (to attach the ultrasonic rodent repellent), a lot of sparks went flying. What am I doing wrong?

 

You shouldn’t loosen that terminal unless power is switched off. There’s still power flowing to the +12V and it keeps hitting Ground, causing short circuits.

You should first disconnect the 12V battery in the rear of the car, and do so by disconnecting the Ground, not the 12V. Whenever you remove a battery (which you don’t need to do) you remove ground first. If you loosen 12V first, your wrench could hit metal as you’re loosing the 12V, sending a lot of current to ground (through your hand, I might add).

 

Yeah, when I hooked up a quick connect wire (for a charger) to that bolt, before doing so I disconnected the negative cable from the battery in back. No problems. Candidly, I didn't think it through that well, but that did the trick: no sparks.

 

When we got back from Florida this spring our old Odyssey which sat in the garage had a problem. The blower motor ran but produced no air. Attached is the picture of the blower motor.

I wonder if I gave the Pesky little buggers a ride when I first turned this on.

 

A few things could be wrong with that. Sparks you can avoid if there's no power when you do it.

But adding some sort of small gizmo like a rodent repeller to that terminal isn't a good idea, unless you are careful to have a smaller fuse in your added line and as close to the terminal as possible. The fuse protection to that terminal is high current and capable of turning your rodent gizmo wires into fire starters.

 

I used caulking to fix the 1/4" galvanized screen rather than screws. It may be messier, but I think it does a great job. I used a pricey product called "Fuze*It" by "Liquid Nails". Should be able to get it at most places you get caulk.
Please correct me if I'm wrong, but I think that the Gen 3 Prius only has one, under-cowl, area to screen protect: at the fire wall near the wind-shield on the passenger side.