Author Topic: looking for permanent solution for preventing mice in blower fan?  (Read 1068 times)

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  • Offline Rock Crawl'n
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The blower fan on our 1999 4Runner keeps getting filled with grass, nuts, etc., likely due to mice, or perhaps a chipmunk. If we clean it out, it just gets refilled---we've tried parking in a different location in our driveway, and dousing the fan housing in Lysol, but even that doesn't seem to be discouraging them.

I've read the many excellent posts on the 4Runner forums on cleaning out the blower fan, but oddly I'm not allowed to start a new thread there until I have lots of replies. I'm hoping folks here will have some suggestions on how to block off the entrance so that critters can't get in.

Also, I'm not particularly comfortable doing anything much more difficult than removing the blower fan (apologies for that---I study mathematics, where "experiments are cheap" :) so my mechanical skills are limited). However, fortunately we live only a couple hours drive from Mudrak's shop, so I could potentially take it there for specialty work if there isn't an easier fix.

I'm starting to get exasperated enough with this that I'm willing to "hit the thumbtack with a sledgehammer" and look into having a snorkel installed (since it'd be useful for future expeditions anyway), or somehow seal things off from underneath, if that would seal things up enough to solve the problem (I'm saying this humorously :) ).

Thanks in advance for any advice!


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A big cat
Make a grate under the cowl so they can't get in
hold this. . .

Lewis Hein

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Hey KauriJ,

I didn't know anyone else on here had studied mathematics. Good for you!

I assume you mean the blower fan for the heater/ac? Our 93 pickup had this problem, only with us it was a mouse that built a nest in the blower: This first came to our attention when I noticed one day that the heat and A/C system smelled like rotting meat and there was lots of junk blowing out of the vents. The air for the in-cab climate control comes in at the louvers right in front of the windshield, with a grille to keep critters out: sometime between 85 and 93 Toyota switched this to a plastic grill which can break or be chewed through.

I would start by inspecting this grille, which should be visible under the sheet metal. A snorkel for the engine will not help this problem, as the two air systems are seperated.


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(Outside) Cat method is highly effective. A little gross when they're chewed up and left on the door step, but better than in your vehicle :thumbs:
:)bestgen4runner [12:45 PM]:   I am so stupid.

Truer words have never been spoken...

KauriJ [OP]

  • Offline Rock Crawl'n
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Thank you to everyone for all the information! This is such a wonderfully welcoming and knowledgeable group on this forum!

@liveoak: thank you for all the detailed info---that'll solve the problem perfectly, and is something I can handle! And,
yes, where I live an outdoor cat would (unfortunately) probably end up as a coyote's dinner.

@Lewis Hein: I'm also surprised to find someone else on this forum who has studied math! I'm currently in grad school working on differential geometry, and hoping to get a teaching/research job after I graduate (partly so I can travel during the summer). How about you?


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I would recommend using 1/4” expanded diamond mesh lath to incorporate liveoak’s idea. It is easily cut with a pair of tin snips and is galvanized so it won’t rust right away, but paint will make it last even longer and will take the shine off it. Lath is thick enough that the rodent intruders can’t chew through it, but flexible enough that you can form it to any contour.
« Last Edit: Sep 17, 2018, 01:08:04 PM by helipilot77 »
-1987 SR5 4runner, 1KZ-t turbo diesel with custom 3" S.S. dump pipe, R-151f transmission, marlin dual ultimate transfer cases w/ triple shifter, SAS, 35's
-1984 SR5 Tercel 4wd wagon bone stock - given to my nephew
-1:10 scale RC 4wd crawler w/yota axles, R2 2 speed enclosed dig tranny and 1st gen 4Runner body by BigBird
-My front axle service write-up


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