Rejecting the rodents: a bit of critter-proofing

  Wildlife can be a real problem for cars sometimes, especially when electrical insulation gets nibbled on.  In the Northeast where I am we have a lot of chipmunks, which tend to live on acorns and other tree-nuts like their bigger cousins the squirrels.  Chipmunks are also burrowing animals, which make holes and tunnels under any handy object like rocks and house walls, and they love crawling into tight little spaces such as the numerous nooks and crannies found all over any modern car.  Fortunately their aim is to simply nest in a protected place and not eat what they find there, but rather bring their food in with them and then let the cracked-open shells pile up.

Engine air filter boxes are a particularly common target, and these li'l buggers will crawl all the way up a long intake snorkel to set up shop in the air box.  I don't quite understand what the appeal is, as the intake tract of a gas car usually smells fairly strongly of fuel.  Maybe they just don't mind that, for the sake of having a safe and often warmer place to sack out.  After finding a few shell fragments in the bottom of the Prius' air box I added a bit of wire-mesh screen across the intake opening, because if left alone the critters will eventually start tearing the air filter itself apart.

The Kona doesn't have an engine air filter but it does have typical car body construction, giving free passage up through the fender areas into the whole under-hood area.  I had already found a few nut fragments kicking around on top of the reduction gear and even the charger.  But far more disturbing, only a few months into ownership I realized that every time I raised the hood I could hear acorns rolling around *inside* its structure as they fell toward the rear edge.  It was rather obvious how they'd gotten there; the hood has four fairly large holes into the structure along the inside of the front edge and generous space under them when the hood is closed.  It was time to get the interior hood liner off and see what could be done.

Hood liner pop-pins The hood liner is held up by very flat fasteners, with no obvious features that a tool is meant to grab.  But bending an edge down carefully shows where the spring tabs are, and by pushing them in on either side the clip can be worked free without forcing and breaking it.

Rodent nest-ball found inside hood Big chewed-out pit in hood liner
I only un-did the clips at the windshield edge and the sides,and let the liner flop down still held at the front edge of the hood.  And the evidence of chipmunk domesticity was immediate -- a big nest-ball dropped out, which had evidently been built from foam chewed out of the thickness of the liner, combined with bits of the fiberglass insulation on the nearby basement wall from the Roxul job.  The negative space of this was a big pit munched out of the liner, stopping just short of penetrating out through the visible black fiber membrane.  The narrowish slits in the stiffening struts are apparently wide enough to let a chipmunk through, so the path from the large holes along the front edge to inside here is fairly obvious.  Some of the acorns must have been left inside the struts, since that's where I heard the rolling.

I can't quite understand why anything would want to sleep on fiberglass, but maybe it doesn't bother a fuzzy critter's skin like it does ours. 

Making hole covers from old hotel keycards So obviously the four large holes along the hood edge needed to be closed somehow.  The rear side of the workspace was blind, i.e. I couldn't access the hidden half of a fastening means from anything other than a hole itself, or I'd have to go into the surrounding material.  The car body parts are well-painted, so I didn't really want to start exposing bare metal for the sake of zip-screwing into it or the like where it would promptly start rusting.  Ideally, something largely non-metallic was needed, and as I thought about the problem geometry, something flexible -- perhaps the bendy edges of the hood liner clips gave me the working model.  Anyway, the junk-box answer was discs cut from old plastic hotel key cards, which I seem to have accumulated quite a few of over years of going to conventions.

Insertion of hole-cover hack Another piece of random plastic yielded backing braces, long enough to bridge the hole edges but short enough to be inserted by one end and then maneuvered back to position.  Sort of the equivalent to toggle bolts, but solid.  The card filler would neatly center into the recessed hole edge, and once the assembly was tightened up, would stay in position.  I could fish a tool in past the card-edge to retain the backing block against spinning as I tightened the zip-screw up; simple thread friction into the thicker backing plastic would keep it in place.  The one metallic part of this wouldn't be in contact with any body metal.

Hood hole fillers installed The fillers went in quite easily, and should suffice for the long term.  I suppose if a chipmunk *really* worked at it, these could be bypassed, but they generally don't manipulate things other than digging holes in dirt.  Usually if something seems like a solid surface they won't think of it as a potential hole to be worked on.  I have to say, though, what they'd already done inside the hood was fairly clever, quite cozy-looking, and very well protected.

[Yes, the example one from before got turned around, and all of them wound up magstripe-out.  The first one I was playing with got dished a little too far to sit tightly, so I turned it around.]

  An alternative approach might have been to build blocks of some material attached down to the large flat expanse of plastic around the front of the hood compartment to align closely enough under the holes when closed, but for now the direct approach was good enough.  I saw no way to get the existing acorns *out* of the hood short of removing it entirely and trying to shake them back toward the front edge, so I didn't bother worrying about it.  I had another part of the project that seemed more urgent, which was to also keep them out of the cabin air intake.  That's another common spot for rodent infestations, and car forums are full of stories about shredded cabin air filters and nests and flying bits of poop and dead mouse bits all through the ventilation system when someone unthinkingly turns on the fan after a car has been sitting for a while.

I had thought about this for the Prius back in the day, but due to a weird dual-layer body construction where the intake sits, it's impossible to get to in any convenient way.  Fortunately, the easy defense is to leave the climate system in "recirculate" before shutting the car down, which blocks off the fresh-air inlet and stays in that position.  Here's the kicker with the Kona: when it shuts down, it *always* opens the air intake to the outside no matter how it was set before.  The controller logic specifically does that by running the flap motor, it's not like it just falls open on some kind of spring arrangement.  I thought about trying to add a switch in line with the motor to disable this behavior, but the actuator and its wiring is buried *way* deep inside the dash.  Not only that, each HVAC actuator motor has a potentiometer on the output to make *sure* it has moved where expected, so preventing that would likely starts throwing some kind of error.  So yeah, that's FIVE wires to every flap control -- motor leads driven by an H-bridge, + and ground to the ends of the pot, and the pot wiper.  It's perverse, excessively complicated, and downright stupid as applied to the intake in question.

It wasn't immediately clear if trying to get at the wiring somewhere else and pull some hack like reversing the motor *and* pot leads so the functionality would be opposite -- that would be one answer, but I wasn't really up for tearing the whole dash apart *again* just for this.  The alternative answer would be screening off the intake if possible, so it was time to investigate the area under the wiper cowl which I had not done yet. It's useful to know what's in there, because if nothing else it wants to get cleaned out every so often.

Giant dump of acorns in Prius cabin filter I had a perfect example of what happens when critters do set up camp in a climate intake.  All of the foregoing discussion aside, I had apparently forgotten to toggle to Recirc mode in the Prius while it was sitting in the yard over a few chilly months -- and the result speaks for itself.  Not only was the filter block hard to extract without spilling stuff all over, I was picking and vacuuming detritus out of the fan and duct for 20+ minutes to try and get most of it.

End panel pops out to expose strut; note squirter hose Okay, so what do we do on the Kona to prevent the same thing?  Short answer, it turns out to be quite easy.  First, there are little covers at each end of the cowl plastic that pop out, revealing the strut bolts -- and a quick look inside past there immediately told me that this didn't have the Prius problem.  With no extra layer of body metal in the way, I was already staring down the throat of the air intake right from here.

These don't even have to come off to pull the cowl anyway, but they do provide a quick and easy way to clean out the drainage areas without major disassembly.  How does Hyundai provide something this simple and elegant and then go out of their way to eff up the intake motor logic so badly??

Little side pieces of the cowl cover There are little end pieces off the corners of the windshield that sort of hook around behind the hood hinge, which need to unclip and come out first.  The one from the other side is sitting here upside down.  It's just little friction tabs to release.

Rubber cap over wiper nut The wipers need to come off; their nuts are under simple rubber caps that just pry out.  14 mm nuts, like on the Prius, but less complex since both wipers are a simple pivot instead of a crazy dual-lever system.  The arms sit on the same type of conical splined shafts, which one must be careful to re-seat properly and not strip.

Popping the fastener pins There are four little expandy-pins holding the front edge down, which can be released by pushing the center piece up.  Then the whole plastic cowl piece easily comes forward away from the windshield edge, and out.  Easy-peasey!

Wiper mechanism The wiper mechanism is tiny, dead-simple, and does *not* need to come out.  This doesn't have a separate drainage tray, it's all just an inherent part of the body design -- so at this point, disassembly is done.

Simple drainage area under the cowl cover The drainage area has fairly generous holes at the ends down into the fender area, and as we can see does tend to accumulate crud.  It's not actually clear if there are larger holes through the bodywork nearby; it could be that these slits are too small for a chipmunk and that there are no other paths.  If that's the case then this is a far more superior and elegant design, and could be why no acorns had shown up in the Kona filter by now anyway.

Expanding fastener holes a little Still, it would be simple enough to slap a screen over the intake and rest assured from then on.  The opening almost seems like it's designed to get some kind of cover -- it's relatively flat, and there's a small open hole at each end.  All I needed to do was expand the holes a little bit, because as I looked at this a plan quickly formed.

Big kit of plastic expandy-pins With another blind-fastening situation, the right answer would be more of those little expandy-pins -- which I'd recently bought a generous kit of on Amazon, aimed at car body work.  The smallest ones wouldn't quite fit until the holes were reamed out.

Critter screen installed The solution is stunningly simple -- screen cut and bent over at the top appropriately, two hold-down clamp pieces of more junk plastic, and two expandy-pins.  Done.  I'm not too worried about the screen in contact with body metal; it is galvanized wire and in very light contact with the paint.  This area isn't really one that tends to rust out anyway.

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_H*   200618