Dead Rat is AC Ventilation system

Hello Gents,
Need to get some feedback please. Discovered a dead small rat in the AC ventilation system. Was able to take the AC fan motor out and removed the stinky dead rodent and am in the process of getting rid of the smell (which isn't pleasant to say the least). Enlisted the help of a friend who is a professional mechanic. We tried to find where the rat entered the system. It did not come from inside the cabin, so we could rule that out. The only place is could come from is inside the engine bay or the wheel well. Although there is evidence rats had been in the engine bay there was no rubber or plastic that the rat chewed through giving it access to the fresh air intake under the wiper grating. We pulled the wiper grate off and found turds in the wiper area but no obvious access to entry through the engine bay itself. The only place we could see that was obvious was a 3 finger gap near the bottom of the plastic wheel well covers. Question, has anyone heard of rats entering through the wheel wells or has anybody ran into this same problem where the entry point is not obvious?
Would appreciate any feedback, thank you in advance.

 

Isn’t that cowel area under the grate open to the fender? Which is then open to the engine bay?

 

Rodents are very flexible. If a rat or mouse can fit their head through a space, their whole body will make it through.
You'd be surprised how small a crack/hole they can squeeze through.

 

New member here but I saw this the other day. I’ll be doing it to my truck hopefully soon. Good luck, damn vermin…
https://youtu.be/SXzvSs2q6Ng?si=qYK8PasyP52JE02u

 

This happened in my wife’s ford Fusion last year. Had a smell one day and the next day started making the “card on wheel spokes” sound as the blower spun. The little thing had deposited a bunch of his organic matter all in the fins of the blower by the time she turned it off. So that was a fun cleaning experience. I wiped everything I could reach inside the ducts with alcohol wipes, then got in there with a duster, then sprayed some fabreeze in. The smell took about a month (regular fan usage) to be fully gone.

I never was able to figure out how it got in, but like the previous commenter said you’d be surprised just what they can squeeze through.

 

Usually there’s fairly large gaps for the intake of the HVAC fan. You usually have to remove the windshield wiper arms and the plastic that covers all the wiper linkage. There should be very large openings in that area. I had issues with mice getting into my xB for multiple years. I finally gave up and removed ALL the interior, seats (save one), and headliner for about 3-4 years. I got sick of that after a while and used clear caulking and stainless steel wire screen over each and every vent hole on the xB. No problems since.

 

Well, this is a 1st gen, so the video above doesn't necessarily apply.

But there's a big ass hole inside the cowl, right over the blower motor, and no cabin filter for the 1st gen, so it's like a gaping entry point I'm sure that little shit used.

Thing is, if they're getting in the cabin, they're getting other places. You probably have nests under the intake manifold you don't know about. They looooove to chew up the knock sensor and starter wiring and make nests out of it, and to nestle on top of the fuel tank and chew the plastics and wiring there, supposedly because the casings have some soy element to them. They also love making nests out of the engine air filter, which can jam up your MAF.

The hole I'm talking about is here, courtesy of BubbaW, the top image shows the location, and the bottom shows the air intake hole (This is also a notorious water leak point, from the two fasteners shown in the top pic): https://tnstatic.net/attachments/cowl-2-jpg.925548/

Proof of rodent damage to other member trucks is in this thread, search the page for RODENT: https://www.tundras.com/threads/so-you-wanna-buy-just-bought-a-1st-gen-tundra-eh.115928/

 

They can also easily sneak in through the rear cab vents...

 

Buy a cheap ozone generator online and run it in there at night after you do all the cleaning you mention, OP. Run it in the daytime with AC on blast too for a few hours while it’s parked.

 

+1 on the ozone generator. I have one and it works well. Before that though, Google "automotive AC foam cleaner". It's designed to clean the coil that's basically impossible to clean otherwise. It does that by foaming up and filling the entire HVAC cavity with cleaning foam. That should help a lot.

 

BG Frigi-clean is KING if you can find cans in your local area. If not, sometimes you can score on fleaBay or scAmazon.

Fair warning: Some of the evap/coil cleaner foams smell OBNOXIOUS. The Toyota branded one has an ammonia undertone I don't love.

 

Hi Everyone. Firstly, thank you all for the input. Should have put it the post that it is a 2003 Tundra. I have a ozone generator going and will continue with the quest to get the stink out. There is openings on both side of the cowling that do lead directly to the fender wells. However with the way the cowling area is designed it is extremely difficult to access the passenger side area of the cowling that is closest to the fender well. It is under a huge piece of metal. I could cut out the metal and gain access but would prefer not to go that route if I don't have to. As mentioned, there are openings on the bottom of the fender wells where they could be access. Have stuffed steel wool in those areas. There is also several opening in the engine bay that allow access to the fender well. I have had the truck for over 8 years now and have never had rodents get into the HVAC system. Currently, they have not been able to get into the cab but if they got into the HVAC than who knows. I live on Vancouver Island in Canada and the rat problem up here is next level. They are always in the engine bays of every vehicle that are parked outside. My friend who is a professional mechanic said that every time they popped a hood they would jump back because a rat would fly out with regularity. In thinking, it would seem my best bet to cut out the top of the cowling and put a grate in the input and seal all the hole that are in the cowling. Sounds extreme but I don't want to deal with this issue ever again and that is where they came in from. Any feedback on this idea would be appreciated. Want to make sure I'm not create a bigger problem buy not thinking it through.

 

If you remove cowl cover on a FGT recommend replacing cowl fasteners as this is common source of leak and wet carpet on pax side

 

Hardware cloth might be a good solution. You can get it at any hardware store or building supply. Comes in 2' (60cm) wide rolls. Cut to fit, bend/shape it to match contours, and fasten in place with screws and washers. Obviously you'll be drilling holes for the screws. I'd seal the holes with RTV or silicone.