Under-Hood Vermin Infestation Issues


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An off shoot of the many problems that the COVID-19 Corona Virus Pandemic brought along is the fact that many of our vehicles… NOT just the GMT-360s and GMT-400-800 Vehicles have had to be parked for longer than ordinary time frames. For some of us, depending upon the region of the countries that we live in across North America, we have to be concerned about the insidious damage being done by… Rodents.

We’ve already have several Members attempting to solve ‘Weird PXXX OBD2 Trouble Code Clusters’ that devolved into discovering their Under-Hood Electrical Wiring Harnesses and Connectors were being relentlessly chewed completely through, causing inexplicable Electrical Shorts and even “NO Start – NO Crank” events.

Armed with the understanding of what the symptoms of Rodent Infestations look like via the attached images, then you’ll have the chance to raise the hoods of all your vehicles… and seek to find any or all of these Tell-Tale signs:

(1) No Start No Crank events on vehicles parked for extended periods of time.

(2) Signs of Chewing Damage from the incessant need of Rodents to Gnaw & Wear Down their Teeth on anything they can literally..Sink Their Teeth Into...".

(3) Obvious signs ...and NOT SO OBVIOUS Signs of Rat or Mouse Droppings. ***

(4) Collections of Grass, Weeds & Animal Fur packed into the various Engine Well Nooks & Crannies. ***

(5) Destruction of the Under-Hood Fiber-Glass and Rubber Hose Insulation performed for Nest Making.

*** THIS Intimate Search and Handling of ANY of this Material may expose you to Inhaling and becoming infected with The Deadly Hanta Virus that makes COVID-19 look like a bout of the Sniffles. This Risk is mostly due to the presence of Common Deer Mouse; a ubiquitous Critter that is the Natural Carrier of this Very Dangerous Virus. Use Extreme Care when investigating and handling any Rodent Species Nests as this brings along the Risk of your Inhaling desiccated, friable, Dried Mouse Feces and Urine Particles.

So... What Should I do...?

(1) Inspect your Dormant vehicles at least Weekly...and Start then Up to Keep Oil in the Upper Block and Check the Battery Strength.

(2) If you find any signs of any Rodent Infestations, place Traps and Baits nearby and underneath the Vehicle. Use care when discarding Dead Rodents... Use Zip Lock Bags.

(3) Treat the areas you suspect might become inviting to this Nest Building by soaking Irritating Peppermint Oil into Durable Rags and stuffing them down into those crevasses and corners where you might find Nesting Material.

(4) Remove ALL traces of Careless Food leftovers (Yup... Having Chocolate Chip Cookies and McDonald's French Fries tucked under the Seats and on the Floorboards is like Ringing the Mouse Dinner Bell).


Note: The attached SUV Images were provided in a related Thread by another GMTN Member... @christo829

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I just had, for the first time, a rodent infestation. While the Saab was parked for the winter, a family took up residence in the glove compartment as evidenced by chewed up fast food napkins. Ugh. I haven't started it yet however I don't suspect at this point they did any damage since they had sufficient nesting material.

They could have been lured in there by the scent of food. I think the first attraction is food, then nesting supplies and then shelter. I think if you eliminate food, you can prevent the majority of unwanted guests.

This guy is the authority on mice, rodents, traps and repellents. Watched quite a few of his videos but actually missed this one. He confirms that peppermint oil is very effective however has to be replenished every month or so.

And this guy shows how to clean out the engine bay and also talks about peppermint oil.

What I would do, if possible, is using that spray bottle with the peppermint oil mix, respray every month or so. If storing a vehicle for a long time, I would use the pure peppermint oil on cotton balls as well as spraying down the whole interior.

This would also be useful for RV's.



Silver Supporter
A squirrel chewed the cooling fan harness on my previous '03 Envoy. Tried sprinkling cayenne pepper dry rub on the wires (after it was repaired), no dice.
Bought a bottle of Mad Dog 357 No. 9 Plutonium and put a few drops of it on their favorite part of the wires. Not only did I not have any damage after that, I never saw the squirrels again...


Pepper spray, that's the ticket!

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