'Does This Hurt the Engine?:' Mechanic Opens Customer’s Hood. Then He Finds Something Unexpected In the Intake Manifold

Car repairs are rarely pretty, but one mechanic turned a grisly discovery into music history while crooning about a rodent sacrifice to the intake manifold in a performance that commenters say was “angelic.”

Mechanic and hopeful R&B singer CJ Roberts (@cjroberts0) lets his Hall & Oates fandom shine brightly in a viral clip with over 602,000 views that features him riffing on the pop hit “Rich Girl” while crooning about a curious, hungry, and very dead rat that ventured too far into a customer’s vehicle. If that reads like a bizarre Mad Libs prompt, give the quick video a look, and all the pieces click into place almost instantly.

TikTok commenters couldn’t get enough of Roberts’ vibrato, with one fan declaring “he hits that ‘IntAaAaAake’ so beautifully,” while another suggested the engine “demanded a sacrifice to be awakened from its long slumber.” Of course, mixed in with the laughter were the serious questions: Does something like this actually hurt the engine, or is it just gross?

The Hidden Cost of a Hole

The answer starts with the filter itself. Air filters are the first line of defense against dust, dirt, and debris making their way into the combustion chamber. To appreciate the danger of a rodent-chewed filter, you need to dig into how filters affect airflow, pressure drop, and engine efficiency. When rodents chew holes through them, particles that would normally be trapped can enter the intake stream, accelerating wear on pistons, valves, and cylinder walls over time. 

Contamination can also damage delicate sensors, such as the mass airflow unit, leading to misfires, reduced fuel economy, and a rough-running engine. In short, a damaged or clogged air filter can significantly reduce an engine's lifespan if left unattended.

When part of the filter media is destroyed, clean airflow can bypass the filtering element entirely, essentially creating a “short circuit” in the filtration process. That allows unfiltered particles to get downstream, but also upsets the pressure dynamics that the engine control system expects.

In research on internal combustion engines, increasing the pressure drop across a compromised filter has been shown to reduce the filling factor (how fully the cylinder charges with air), decrease available power, and increase specific fuel consumption. In one study on diesel engines, increasing the filter pressure drop significantly reduced maximum power output and degraded engine efficiency.

In simpler terms, a damaged or clogged filter forces the engine to work harder to draw in air, which can cause the ECU to adjust fuel delivery in ways that lean into performance losses or long-term wear. Over time, that damage accumulates, and if a hole is big enough, the engine is essentially breathing in grit. The worst case isn’t just lost horsepower, but permanent abrasion to rings, cylinders, and valves.

When the Rodents Strike

But what about the rat itself? Mechanics who’ve seen similar cases say the results vary from a clogged intake to catastrophic failures. Smaller remains might burn off without much damage, but bones or fur sucked into the manifold can obstruct airflow, clog injectors, or even score cylinder walls if fragments make it past the valves. On turbocharged engines, things can get especially ugly, since foreign objects sucked into the compressor wheel can damage both the turbocharger and intercooler, with repairs that easily stretch into the thousands.

There’s also the electrical side. Rodents are notorious for chewing wiring harnesses, especially in newer cars that use soy-based insulation.

Rodent intrusion into engine bays isn’t an equal-opportunity problem, and tends to spike when the weather turns cold. During the fall and winter months, rats and mice seek warm, sheltered environments, driving them toward vehicles parked outdoors or in unheated garages. In colder regions or rural areas with nearby woods, barns, or brush, cars become attractive nesting spots simply by being quiet, dry, and off the grid.

Mechanics in colder climates report a clear bump in rodent-related damage after the first frost. For owners, that means the risk isn’t just “if,” but “when.” If your car sits idle for long stretches in a region with seasonal cold snaps, it’s wise to check underhood spaces more often. Disconnecting battery connections or running the engine periodically won’t prevent rodent invasions, but simply opening the hood and visually inspecting the filter or intake housing can catch trouble early,  before a rat becomes a lyrical subject or a repair bill.

Toyota, Honda, and Subaru have all faced lawsuits over rodent-related damage, with some owners reporting four-figure repair bills due to chewed ignition coils, damaged harnesses, and even complete no-start conditions.

That cost reality explains why one commenter groaned, “Ugh this cost me a couple hundred once. Rat guts everywhere.” Meanwhile, another recalled a pack rat that ended up in cylinder three. The joke posts about “forbidden pâté” and “Icarus [flying] too close to the sun” were amusing, but behind them lies a real problem that mechanics across the country face every winter.

Experts recommend keeping food away from vehicles, especially if they’re parked outside for long stretches. Ultrasonic deterrents, peppermint oil sprays, and rodent tape can make engine bays less hospitable to rodents. And for cars that sit unused, simply popping the hood for a quick inspection can prevent a rodent surprise before startup.

For Roberts, though, the unlucky rat was less a maintenance headache than a musical muse. By transforming a customer’s problem into a viral moment, he gave TikTok a performance that one fan called “better than the second version of the song ever.” And while the rat may have been lost to the intake, the Hall & Oates remix lives on, scratching brain folds “in a good way,” as another viewer put it.

Motor1 reached out to Roberts via direct message. We’ll be sure to update this if they respond.