Mouse nest in heater fan, and suggestions for prevention

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Ace
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My tercel:: '83 DLX 4WD Tercel wagon 3AC

Mouse nest in heater fan, and suggestions for prevention

Post by Ace »

I live in a rural area where wild mice are a fact of life. I used to have outdoor cats for rodent patrol, but not lately. I did a forum search and noticed that some of you have had mouse infiltrations, although I think those were mostly on unused parts cars?

This summer my Tercel (primary transportation vehicle) has typically sat for 2 or 3 weeks between uses. I park the car in an open-sided shed. One time I go driving, there are bits of black foam blowing out of the vents. I suspect a mouse situation, but I couldn't see how mice could get in there. The black foam all blew out, eventually. There was no clear evidence that mice had been in the passenger compartment of the car. A week later I set multiple traps in the engine compartment and caught two mice and a chipmunk overnight. Next night, nothing.

Next time I drive, bits of white upholstery stuffing are blowing out the vents and the fan sounds like it's loaded up with material. So I figure I have to take it apart and sure enough, the squirrel cage fan unit has a big handful of mouse nest material. I clean it out, put it all back together. Fortunately it wasn't too difficult to take the fan unit out but it would have been easier if I had known the proper sequence of removal for some of the ductwork. The FSM does not have instructions for this.
100_3115.JPG
I felt around in the ductwork for additional debris and yanked on the fan speed resistor wires before I realized what they were. Fortunately I managed to straighten them out, and didn't do any serious damage. Don't make that mistake!

I still am not sure how mice got in there, and I certainly want to prevent any recurrences. The simplest precaution is to park the car with the air control lever in "recirculate" position. This physically blocks passage from the cowl air intake to the squirrel cage area. As far as I can tell, the mouse may have gone down the cowl air intake from the hood. I wouldn't think they could go through the grating in there; I see no other passage, but I need to check underneath the car some more. Mice can get through small spaces but not real tiny spaces; they need a minimum space to get their hard skull through.

Although mice were in the squirrel cage on the upwind side, there was no evidence that they went through the fan blades into the heater area. Apparently they built the first nest with bits of black foam picked off the inside of the air recirculate door. That material was small and light enough to all blow through. Then they apparently rebuilt the nest with material taken from the upholstery of a derelict old pickup parked next to my car! It seems crazy they would take material out of one vehicle (which was not so hard to get into) and put it in another. Apparently they were intent on saving that nest location, after starting with it?

I suspect this is pretty rare (?) for a mouse to get into a Tercel fan unit on an active intact car, but it has happened to me. I've parked in that space for years and one mouse finally scouted it out. Anyone else have problems like this? I did not have any food in the car and I suppose they were just seeking secure shelter. Stupid pesky mice, if they only knew what they were getting into.


If you want to remove your fan and blower unit, it is somewhat easier with instructions. This was a 1983 Tercel DLX without AC.

1) Remove glove compartment unit, 2 screws. Glove compartment with door is all one unit.
2) Remove strut across the bottom of glove compartment space, 2 screws. Unplug the buzzer unit which is attached to the strut.
3) Unclip the control cable connection for the air recirculate door on the fan unit, no tools.
4) Remove 2 pieces of black plastic ductwork which go to the right side dash vent. One screw in each piece.
5) Remove large white plastic duct between the fan unit and heater, three 10 mm bolts. This duct will pull straight back and clear.
6) Unplug electrical connection to fan.
7) Remove fan and blower unit, three 10mm bolts. It comes out fairly easy after removing the previous items.


When I get more ambitious I will look over the underside of the car to see if there is any other possible entry point for a mouse to get into the cowl air intake space. I know the cowl space has drains that go down from near the bottom corners of the windshield. Where I live, the car hasn't had any serious rust that I know of.
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TominMO
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Re: Mouse nest in heater fan, and suggestions for prevention

Post by TominMO »

Ace wrote:It seems crazy they would take material out of one vehicle (which was not so hard to get into) and put it in another.
Why? We do it all the time! :lol:

Anyway, glad you figured it out and got it taken care of. I think there are instructional posts on how to get to the heater parts most efficiently.
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Re: Mouse nest in heater fan, and suggestions for prevention

Post by ARCHINSTL »

Ace - check out this thread: https://tercel4wd.com/forums/viewtopic.php? ... ilit=drain
I've had no meeces in the ductwork or blower since I plugged the cowl bottom drain holes with mesh and blocked the big duct to the back seats (under the console binnacle).
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Petros
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Re: Mouse nest in heater fan, and suggestions for prevention

Post by Petros »

we get them here all the time, even on cars that are daily drivers left to sit over a weekend.

My daughters Suzuki car got a fresh nest of live mice, when she turned on the fan it make a "funny noise", and asked me to look at it when she got home from class. I pulled the blower and found a nest and two freshly killed mice, good thing I removed it that day.

How about a pet snake? I do not now how to stop it, I notice it is more common if I park on grass, even for just a day or two (even mowed grass that does not touch the underside of the car).

There are electronic mice replants they sell at hardware stores, I have not tried them, but being battery powered it could be placed in the car when you park it.
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'84 Tercel 4wd (daily driver, with on going mods)
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Ace
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Re: Mouse nest in heater fan, and suggestions for prevention

Post by Ace »

Thanks for the link and info. Now it is obvious to me that critters can go right up the cowl drain. The car was caked with mud until recently and I finally washed it and looked under there (with camera). I can stick two fingers up that gap, maybe big enough for a chipmunk. If you pour water into the cowl, this is where it comes out right behind the mudflap. I'll have to put some screening in there.

Thinking of 1960's GM vehicles I have had, those drains were just small gaps that could plug up and cause the lower cowl space to rust out through the side of the fender. I had no idea the Tercel had such big gaps there!

With my Tercel, I now know that I can leave the air control on "recirculate" to physically block pesky critters from getting into the blower unit and internal ductwork, if they happen to be wandering around in the cowl space.
IMG_3437.JPG
When I had left the car caked with mud, it might have given the critters an easier climb up the mud flap and into the cowl drain opening.
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dlb
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Re: Mouse nest in heater fan, and suggestions for prevention

Post by dlb »

we have a cat that lives outside and is a fantastic killer. i have never had any problems with any rodents in any of my cars, regardless of what tasty morsels my wife leaves in them. i recommend everyone get a barn cat.
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Petros
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Re: Mouse nest in heater fan, and suggestions for prevention

Post by Petros »

house cats eat very large quantifies of rodents, the amount was unknown until some biologists studied it. Over 20 billion rodents a year are killed by house cats in the united states alone found by a 2012 study.

article here: http://www.huffingtonpost.com/2013/01/3 ... 75833.html

quote from the article:
"Biologists estimated that cats are responsible for the deaths of as many as 3.7 billion birds and 20.7 billion smaller animals, including mice, voles and chipmunks, the Agence France-Presse reported. The study also concludes that cats are likely the No. 1 killer of birds and small mammals in the country.

Led by Scott Loss of the Smithsonian Conservation Biology Institute, the study drew from past research on the predatory habits of cats. While previous studies have suggested cats are responsible for billions of small creature deaths, the most recent estimates are significantly higher.

"The magnitude of wildlife mortality caused by cats that we report here far exceeds all prior estimates,” the report stated, according to the International Business Times.

In the new study, researchers surmised there are about 84 million cats owned in the U.S. They estimated that each cat kills between four and 18 birds per year and eight to 21 small mammals annually, LiveScience reports.

However, it's feral cats -- an estimated 30 million to 80 million of which live in the U.S. -- that pose the greatest threat. As LiveScience notes, each of these unowned cats kills 23 to 46 birds and 129 to 338 tiny creatures per year.

Though the study was limited to U.S. cats, the murderous tendencies of felines are not."


hah hah, note the tone of the article, like the cats are doing a bad thing! "murderous tendencies" indeed. If not for cats we would be OVERRUN with rodents!!!
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
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Re: Mouse nest in heater fan, and suggestions for prevention

Post by Highlander »

You might try a dryer sheet at the lower opening of the cowl drain. I've had the same problem with squirrel nests on top of my 460 V8 plow truck and my 4.3L V6- Igot the suggestion of using a dryer sheet from the Sprite forum, and so far no squirrel nests on my V8. Just be sure to put it away from a high heat point (hard to do on that big motor). The smell repels the rodents (hell, it repels me!) and they're CHEAP!, just steal one from SWMBO and you're golden! :lol:
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Ace
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Re: Mouse nest in heater fan, and suggestions for prevention

Post by Ace »

Yeah, cats are good to have around but I've lost several to other predators, and currently don't have cats cuz I'm not always there to feed them. I should clear back some of the bushes around my place so the hawks and owls can do their job better.

Thanks for the tip on dryer sheets. I've used strong-smelling deodorant soaps like Irish Spring as rodent deterrents in outbuildings, it seems to help. Plus I intend to put some screening up the Tercel gaps, I don't want any more critters up there.

I was remembering that 3 or 4 years ago my Tercel wouldn't start and I discovered a wire to the igniter that looked possibly bitten off. One time the lower radiator hose on an old pickup was nibbled over the winter and I lost 4 gallons of antifreeze, plus the odd-shape hose was somewhat expensive to replace. Since then I've put aluminum foil over the hoses of rarely-used vehicles which seems to have deterred rodent nibbling?
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Re: Mouse nest in heater fan, and suggestions for prevention

Post by Petros »

honda some years ago, and many other car companies followed, to make their wire insulation and rubber parts "green" by using soy bean based plastic. It is not only non-toixc, but also has some food value, and the mice will come in and remove all of your wire insulation and eat all of the rubber parts away if you park in a grassy field. This was a very bad idea.

cleaning out a mouse nest every once in a while is no problem compared to that.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
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Re: Mouse nest in heater fan, and suggestions for prevention

Post by dlb »

Ace wrote:Yeah, cats are good to have around but I've lost several to other predators, and currently don't have cats cuz I'm not always there to feed them. I should clear back some of the bushes around my place so the hawks and owls can do their job better.
we actually don't feed our cat much. it keeps him hunting lots. we feed him more regularly in the winter to keep him fat and warm since he lives outside year round but spring to autumn, anything we feed him is just a bonus on top of his killings. that's why i like cats. we can go away for weeks and they're fine on their own.
Ace wrote:Thanks for the tip on dryer sheets. I've used strong-smelling deodorant soaps like Irish Spring as rodent deterrents in outbuildings, it seems to help. Plus I intend to put some screening up the Tercel gaps, I don't want any more critters up there.
i actually had rats steal my bars of soap from the outdoor shower in a place i lived for a while. at first i thought my room mate was just super cheap and keeping them for himself but i asked him after several had disappeared and he had no idea about it. we figured it was the rats (you could hear them in the walls and ceiling) and sure enough, when my buddy did some major renos on the place he found a bunch of soap up in the ceiling, along with all kinds of other crap. long story short, i've found rats love soap so i wouldn't use that.
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Re: Mouse nest in heater fan, and suggestions for prevention

Post by ARCHINSTL »

dlb wrote:i've found rats love soap...
Do they shower together...? :shock:
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Re: Mouse nest in heater fan, and suggestions for prevention

Post by TominMO »

At least you have clean rats. Do they also steal shampoo or deodorant?
1986 4WD Tercel, formerly gold, now camo
1995 Ford Aspire SE, MPG development car, shooting for 65 MPG hwy
1990 Ford Festiva, mild motor swap, HP development car
The other Tom M. in STL w/a gold 1986 SR5--from the universe where Spock has a goatee
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Re: Mouse nest in heater fan, and suggestions for prevention

Post by Petros »

you might have to alter your expectations when someone uses the expression "I smell a rat". Lavender perhaps?
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
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Re: Mouse nest in heater fan, and suggestions for prevention

Post by stanrob »

To Ace: I want to thank you for providing instructions. In another thread I started before I saw this, Petros also gave instructions. I'm struggling with both! For details, view the "Access to heater blower" thread.
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