What Are Drivers Reporting Underneath Their Vehicles?
Raccoon Machines continuously analyzes recent NHTSA vehicle-owner complaints to identify reported conditions that could potentially be seen during a visual underbody inspection. Complaints are screened, classified, and grouped into external fluid leaks, rust & corrosion, and visible physical damage to track how these issues appear in current owner reports.
CURRENT ANALYSIS: 2025–2026
181,821 NHTSA vehicle-owner complaints analyzed
Last updated: August 14, 2026
Source: U.S. National Highway Traffic Safety Administration (NHTSA) Vehicle Owner Complaint data.
6.29% of Recent NHTSA Complaints We Analyzed Describe Something Potentially Visible Underneath
11,434 of 181,821 complaints
Among the recent NHTSA complaints we analyzed, 6.29% described an external fluid leak, visible physical damage, rust or corrosion that could potentially leave evidence underneath the vehicle.
1 in 16 complaints
This does not mean that one in 16 vehicles on the road has an underbody problem. It means that among owners who submitted complaints to NHTSA, approximately one in 16 reports we analyzed included a condition potentially observable from underneath.
What Shows Up Underneath?
Underbody-visible problems are not all the same. We grouped recent complaints into three practical categories.
External Fluid Leaks: 3.40%
External leaks involving engine oil, coolant, fuel, transmission fluid, brake fluid and other vehicle fluids that could potentially leave visible evidence underneath.
Visible Physical Damage: 2.65%
Reported broken, cracked, bent, loose, detached or otherwise damaged components accessible or potentially visible from underneath — including suspension, axles, exhaust, frames, subframes, mounts, lines and shields.
Rust & Corrosion: 1.31%
Reported rust or corrosion affecting structural or mechanical components potentially visible during an underbody inspection.
How Does Vehicle Age Change the Picture?
Vehicle age produces three very different patterns.
Vehicle Age Tells Different Stories
Rust follows age.
Rust and corrosion show the clearest relationship with vehicle age. Rust-related complaints rise from 0.13% for vehicles 0–5 years old to 0.93% for vehicles over 10 years old, more than a sevenfold difference.
That pattern is not surprising. Older vehicles have accumulated more years of exposure to moisture, road salt, weather, heat cycles and ordinary use. The underside is also where many exposed structural and mechanical components live.
Leaks appear to peak in middle age.
Leak-related complaints increase from 0.85% among vehicles 0–5 years old to 1.64% among vehicles 5–10 years old, nearly doubling.
This is also a reasonable lifecycle pattern. After years of service, seals, hoses, connections, gaskets and other components begin to age and repairs become more common.
Interestingly, the reported share falls again to 0.91% among vehicles over 10 years old.
That does not necessarily mean older vehicles leak less. Complaint data can also reflect previous repairs, vehicles leaving service, survivorship, and differences in what owners of older vehicles consider significant enough to report.
So the 10+ decline should be interpreted cautiously.
Visible damage barely cares about age.
Visible physical damage tells a very different story. Its share is almost perfectly flat: 0.87% → 0.89% → 0.89%
Broken, loose, bent or damaged components can result from impacts, road conditions, component defects, repairs or individual failures. Those events are not necessarily tied to vehicle age. A relatively new vehicle can have something worth seeing underneath just as an older vehicle can.
Three Problems. Three Different Patterns.
This is one reason we track the categories separately.
Rust accumulates. Time and environmental exposure matter.
Leaks have a lifecycle. They are relatively uncommon in newer vehicles, rise substantially in middle age, and become harder to interpret among older vehicles.
Damage can happen anytime. The data show almost no relationship between visible physical damage and vehicle age.