Once you find/clear the nest you'll need to neutralize the urine odor. Mice urine is some of the worst there is. Just a little bit will linger for years and drive you nuts. A lot of the commercial products just don't work very well. Myth Busters did a segment on this very thing a long time ago and came up with a solution that was based on chemistry. It works on other pet urine as well. Wash the affected area with a solution of 1 quart of 3% hydrogen peroxide, mixed with ¼ cup of baking soda, and 1 teaspoon of mild dishwashing liquid (something with a lemon-y scent is nice, but optional). That should take care of the odor for good.


My story: Mice had set up shop in my Land Rover's heater box. The urine odor was SO BAD I couldn't stand driving it with all the windows down on a 40* day! After a good wash and drying of the heater box (inside), the odor was completely gone, has never come back. Even to this day (7yrs later and a lot of hot sunny days) you cannot smell a hint of mouse.

In my case I didn't remove the heater box. Its a lot of work on a Land Rover because they are in the middle of the dash. I removed the blower and sucked the next material out with a shop vac. Also sucked out the nest material further inside the heater box using a piece of 3/4" hose hooked to the shop vac hose. I used a borescope camera to ensure I got all the nest materials. Then I mixed the solution (above) in a bucket with a mini submersible Harbor Freight water pump at the bottom of a bucket ....and a home-made 90 degree spray nozzle on a flexible hose. I fed the hose inside the heater box and rotated the hose by hand ....verifying my movements and the spray with the borescope. I washed the entire inside of the heater box with solution a couple times. Most of the liquid went down the A/C drain. Any other liquid I cleaned up with the shop vac. It was a lot easier than removing the heater box.

Like I said it was a major success. Good luck. Hope yours is too....

Edit - I was able to dig most of the mouse nest out with my hand. What I needed to shop vac out, I did outside with the shop vac downstream (in the wind), I was wearing a mask. Don't use a shop vac on mice in an enclosed area.

 

Mark G, Thanks for sharing your experience. To make sure I do it right, I think you’ll need to show me how to do it and I think I’ll be OK. I live in NH. Seriously, thank you.

 

....I added an 'Edit' to my post above that I was careful to use a shop vac only outside on a breezy day (wearing a good dust mask).

 

Reading all of the great information has lead to another question.

Am I looking for two areas 1) the nest and 2) the bathroom?

Thanks

 

just wait till that gets hot from the trans and exhaust. It’ll cook off in a few years.

Scrape and vacuum as much of that as possible. Put some rust paint of some kind on top of you can get into it.

 

If your car is a Non A/C car check the fresh air vents in the kick panels

under hood, behind the screens on either end of the wiper tray

on top of the transmission. Love to eat the insulation there

when I bought my 78 there was a nest behind where the rear speakers would have mounted. Down low almost under the pull shade.

Remove the seats and check between the carpet and the padding.

 

The latest mouse nest I found in a rear storage compartment. Previously they where in the blower fan and related ductwork. Didn’t get it completely cleaned out until I changed the heater core. Mouse poo, nesting material and seed debris had rained down onto the evaporator. With the squirrel cage pulled aside I put a vacuum hose down on one side of the evaporator and blew compressor air in the other side.
It looked to me they were getting in thru the cowl plenum duct. They had chewed on the plastic screen there and gnawed holes in the fan motor cooling tube. I added an activated carbon filter and a fibered air filter over the top of the plastic screens to make them both function as modern cabin-air filters and keep the mice out. What really works though is aggressively trapping the mice. I had to keep changing bait to find what they like.

 

Thanks Kerschmolar,
My head is spinning trying to keep up with the terminology, I'm using an '82 Factory Assembly Manual to help me out. Please correct me if I'm wrong. The process you describe is all done from inside the engine bay, correct? Is anything done from inside the vehicle?

A PO already installed metal screen in the two areas where you installed the air filters however, there's plenty of room for a mouse to get through.

 

Thanks for the tip on adding the filter.
I might put some 1/4" mesh screen in those corners. I added fire wire mesh (1/4" holes) over the air intake of a couple vehicles I have (incl the Land Rover). Easier to do it on the front end.

 

I did the mouse-mess cleanup in tandem with replacing a leaky heater core. As mentioned above the c3 is built around the heater core. Getting the heater core out requires disassembly of the passenger side dash and removing the ductwork. That’s how I accessed the downwind side of the evaporator to blow in compressor air. The blower fan comes out into the engine compartment, but it’s really hard to work on with the coolant overflow reservoir in the way. Removing the reservoir requires the compressor be disconnected from its support brackets to get it out of the way. Someone on another post borrowed someone with little hands to help! I don’t have any experience in removing the evaporator box from the engine side. None of it is not hard to do, just takes time.
I liked the idea of using a little camera on a fiber optic cable to pinpoint what needs to cleaned out before too much disassembly.

 

Too funny! Just finished posting about mice and look what the cat brought to the door.
What’s better than a cat? ...4 cats!!



Sir Henry, Minka, Theodora and Rufus

 

***UPDATE****
I found the nest in the center console on the passenger side. They chewed through a speaker wire and the insulation on the antenna wire.
I’ll be cleaning the area with Mark G’s solution.
I can’t find any but are there any holes under the center console where they could get in?
There’s no detectable small in the car right now but I’m sure I haven’t smelled the last of these rascals. I have a bore scope on order and will be inspecting the duct work as best I can.
On a surprise note. I was tracing the sound system wires to the back and a PO had put a plastic tray in the compartment behind the passenger seat which I always thought was strange. I finally took the time to remove that tray and there it was...the original unused jack, lug wrench and hold down spring. I had bought one on EBay about six months ago.
I’m off to splice wires and scrub the area. I’ll let you know of any major developments.
Thank you to all who helped me out.

The speaker wire is on the bottom and chewed through. The antenna insulation is chewed off to the right.

The nest was on the passenger side only.

 

Count your blessings! My mouse died in the blower duct and required quite a mechanical expedition to get the body out. Took years to get the smell out completely. I now use 3 sonic repellers inside the garage and multiple box door traps baited with peanut butter outside. So far has worked. Catch about one a week now.

 

I bought a home in a rural area that has a 4 car garage outbuilding. It was infested with mice, rats and squirrels. The attic insulation was mostly missing, there was electrical wire damage, chewed facia and soffit, and feces and urine everywhere. The mice would eat the bait off the rat traps without tripping them and the rats/squirrels would carry off the mice traps. Outdoor cats were the solution. Once the rodent problem was under control there was were less copperhead/snake issues due to a reduced food source. The cats would also kill young snakes.

I then experienced a cat loss to coyotes. This seems to be under control due to my use of chicken farmer neighbor recommended wolf urine. Not sure if its really wolf urine (it stinks) or how they actually collect wolf urine but it seems to be working.

 

FWIW, look around your winter storage location to answer the "why" the mice moved in. Maybe it was easy access to a warm space, maybe it was food. This will prevent them from coming back next year.

Short version of a long story; right after we bought our lake house a few years ago, we started seeing some deer and thought it'd be nice to have them around so I put up a small deer feeded. I put corn out and sure enough, the deer started coming around...so did the mice. I didn't notice at first but they had gotten into the corn bag stored in - you guessed it - the garage with the Corvettes, Jet Skis and boat. The little buggers started stashing corn everywhere, including in the cars and Jet skies. Fortunately I never found any nesting and I removed the food source and killed several mice in traps so all ended well...for me and my cars anyway, not so much for the mice.

 

Check out this guys C3 video on the heater/AC system clean out and repair.

 

Speaking of mice; I've had a couple run-ins with them in the ten years we've lived in this house. First time we let the pros handle it. They sealed up all possible entry points/set out traps. That worked for about three years, but now starting to hear em again. I resealed one of the entry points that previous Pest control guys found. Problem is I think there might still be a few up there (attic). So now I'm baiting attic with rat poison (green stuff with diphacinone) and it seems to be working. The question is: If you ask ten people how rat poison works, 9.9 of them will tell you that it makes rats thirsty so they leave your house to get a drink/die. If you google it you get the exact opposite, i.e., "Rat poison does NOT make them thirsty; that is a myth."

So mice experts, which is it?

 

Never-never-ever use poison in a household.
Does the poison work?
Absolutely!
Do the mice leave the homestead when they die?
What do "YOU" think?

Took eight months to get that stench out of a bdrm heat duct.
Never again. No poison within 50 ft of my house.

And as a side note:
The 5 gal bucket-Walk the Plank trap is the best out there.

 

Depends on the type of poison...some make them deadly thirsty (anticoagulants) and some kill them almost immediately on the spot (strychnine). Many states and countries have outlawed the latter.

 

I'm not a fan of poison either, for reasons listed above, never know where they'll die in the house.. We use the sticky traps, baited with popcorn. Sucks for the mice but they shouldn't be in my house/garage.