Déjà Vu: The Mouse-Infested Armada

My readers will certainly recall The Case of the Mouse-Infested Truck—the 2008 Silverado I bought from my ex-employer for a song because mice had used it as both a bathroom and a casket (Google “Rob Siegel Hagerty mouse infested truck,” but be sure you don’t have a weak stomach).

So imagine how I felt when I had to admit to myself that my recently-purchased 2008 Nissan Armada—ostensibly the replacement for the Silverado—had a rodent contamination issue.

When I bought the Armada, it had been sitting on the owner’s property for a few months. As I explained here, it had a number of problems that I was aware of and several more that I wasn’t. During the short test drive, I thought I caught a rodent-tinged whiff, but it was nothing close to the gag-inducing stench from the Silverado. There was, however, an obvious climate control issue—a clicking sound emanating from the heater box. This is the characteristic mating call of worn-out plastic gears on the actuator controlling one of the blend doors. But with all the truck’s needs, these two issues didn’t even make it onto the punch list.

Once the Armada was largely sorted out and I began driving it, however, the slightly acrid, rodent-infused background smell was like a thistle thorn in a sock—annoying as hell for short periods. However, when my wife accompanied me on a short errand, she of the exquisitely sensitive sense of smell said that nothing jumped out at her. So I went to my backup position—denial. There is no smell. There. I dealt with it. Done.

Until one night. I had a gig, my daily-driver E39 BMW was sidelined in the garage, and my wife needed her Honda Fit, so I drove the Armada 40 miles in the rain each way. The combination of the closed cabin and the need to run the blower fan with fresh air to defrost the windshield made the eau-de-mouse smell jump to the foreground. My state of denial crumbled.

Damn.

The mouse-infested Silverado had been a nightmare scenario, as mice had crawled up the A-pillars into the headliner, urinated and defecated and died there, and did the same inside the heater box. To deal with it, I removed the headliner, threw it in the garbage, cleaned every metal surface on the roof and pillars with enzyme-based cleaner, and installed a new headliner. Unfortunately, I read that removing and reinstalling the heater box was something like a 12-hour job, and I wasn’t willing to do that, so instead I snaked an inspection camera down the vents and into the box, located the mouse nest, drilled an opening with a hole saw, pulled out the nest and the body of a dead mouse, and tried to clean the box using multiple treatments of pressurized disinfectant that washed out through the drip hole for the A/C condenser. It worked well enough for me to be able to use the truck (and for my wife to even ride in it with me, if necessary), but it also made me think that I would never knowingly buy another mouse-infested vehicle unless it was something I really REALLY wanted and was a smoking-good deal. The Armada was neither of these things, so the fact that I had to admit that I was facing the possibility of going through all this again really frosted my behind.

And then I had a thought: Maybe this time I’d get lucky. Yeah, let’s go with that.

Any vehicle built in the past 30 years has cabin air filters. It’s not uncommon for them to be a poster child for lack of maintenance—that is, for the filters to never be changed, and for all sort of nasty stuff to accumulate on them. Including mouse nests.

So, I said to myself, “Self, don’t panic. Check the cabin air filters.”

The location of cabin air filters varies car-to-car, but they’re usually up high on the inside of the cowl. Thus, it’s not unusual for them, or for one of them, to be above or behind the glove box. That’s where they are in the Armada. On many cars, you can reach the filter with the glovebox installed. On some, you need to unclip the glovebox so it drops further down than it normally does. But in the Armada, you actually need to unscrew and remove the entire glove box assembly, including the frame the glovebox pivots on. It was surprising, but not too bad

Once the glovebox assembly is removed, the filters are accessible. The filter cover is held in place by a single 10mm bolt.

I withdrew the two filters. They were, as we used to say in junior high, grody to the max. If they were ever replaced, it certainly wasn’t recently.

In case you need a close-up, here it is. No wonder the cabin air smelled like rodent. I became very hopeful that this was “it,” and ran inside to the laptop and put a $12 pair of filters on order for next-day delivery.

As Ron Popeil used to say, “But wait! There’s more!” Once the filters were removed, I looked back at the fresh air vent above them.

Jackpot.

This mouse nest appeared to have been completely above the filters, giving me hope that, unlike the situation in the Silverado, contamination hadn’t extended into the heater box. My iPhone inspection camera had stopped working for some reason, so instead I pulled out the blower fan to gain inspection access to the heater box. This was fairly straightforward, as it’s only held in place by three 5.5mm bolts. With the blower fan out, I could stick my phone inside the heater box and photograph it, or at least the core that the fan blows through. I saw a few stray leaves and stems, but no evidence of rodent contamination—no nests, no pellets.

Once I’d confirmed the apparently limited scope of the contamination, instead of doing the full-on pressure-washing with enzyme-based cleaner approach I did with the Silverado, I simply reached in and wiped every surface I could reach with Clorox disinfecting wipes. I also sprayed and wiped each blade of the squirrel cage of the blower fan.

Although I hate the smell of Lysol, this was good time to use it in moderation. Let me be clear about this: If there is a mouse nest, or piles of dung, or an actual carcass inside, unloading a can of Lysol into the vents as some people propose online is never going to make the smell go away. Unless you’ve located and removed the bulk source of the smell, all that spray disinfectant is likely to do is mask it. However, using a bit of spray disinfectant to chase down residual reengage molecules either above or below the actual contamination isn’t unreasonable. I reinstalled the blower fan and the filter cover but didn’t install the filters yet. I then turned the fan on high, set the climate control to fresh air, gave a blast of Lysol into the fresh air inlet in the windshield cowl, and let the blower fan suck it directly into the heater box without the filters blocking it. I let it run in my driveway for 15 minutes. Then I installed the filters and let it run for another 15.

Finally, with trepidation, I took the Armada for a drive. Windows up, fresh air selected, blower on full.

The smell was gone.

It took me a while to notice that something else was gone too—the clicking sound. Either it’s an utter coincidence, or what was happening was that the sound was coming from the fresh air vent being unable to close because it was hitting the mouse nest on top of the filter, and with it gone, it now could move unimpeded.

As I said, sometimes you get lucky.

Next, I need to look at the air conditioning. Maybe I’ll get lucky with that too.

***

Rob’s latest book, The Best Of The Hack Mechanic™: 35 years of hacks, kluges, and assorted automotive mayhem is available on Amazon here. His other seven books are available here on Amazon, or you can order personally-inscribed copies from Rob’s website, www.robsiegel.com.

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