About the data

This page is the one to read before you trust anything else on this site. It says plainly what the data is, and what it is not.

The single most important limitation

The complaint database has no denominator. It records how many people filed a complaint. It does not record how many of those vehicles were sold, registered, or are still on the road.

So a model with 1,700 complaints is not worse than a model with 300. It may simply be far more common, or older, or owned by people more inclined to file. Complaint counts on this site must not be compared between models. That is not a disclaimer bolted on afterwards — it is why this site shows the breakdown within a single model year instead of ranking models against each other.

What can be read is the shape of the data inside one model year: which components come up most often relative to that model’s own complaints, and what share of its complaints reported a crash, a fire, an injury or a death. Those are statistics within one sample.

Complaints are not verified

Anyone can file a complaint with NHTSA. The complaints are not investigated, confirmed or technically assessed before they enter the database. A complaint records that someone reported a problem — not that the problem occurred as described, nor that it was caused by a defect. Some are duplicates. Some are later found to be unrelated to the vehicle.

This is still useful information, because volume and clustering by component are informative in aggregate. It is not evidence about any individual car.

Sources

All data comes from the U.S. federal government and is in the public domain:

• Consumer complaints — NHTSA complaints API (api.nhtsa.gov/complaints/complaintsByVehicle)
• Recall campaigns — NHTSA recalls API (api.nhtsa.gov/recalls/recallsByVehicle)
• Crash-test ratings — NHTSA NCAP Safety Ratings API (api.nhtsa.gov/SafetyRatings)

Data on this site was retrieved on September 9, 2026.

How the numbers are computed

• Component groups. Each complaint names one or more components, using NHTSA’s own category names. A complaint naming two components counts once in each group, so the shares on a page add up to more than 100%. Where a complaint names two sub-components of the same system, it counts once for that system.
• Component names are NHTSA’s. They are shown in normal case rather than the database’s capitals, but the wording is not changed. NHTSA’s own category list has changed over the years, which is why a page can show both “Engine” and “Engine and engine cooling” as separate groups.
• Severity shares. The share of that model year’s complaints in which the filer reported a crash, a fire, an injury or a death. One complaint can report more than one, so these do not sum to 100%.
• Bar lengths are scaled within a page, to that page’s largest component group. They are not comparable between pages.
• Checklist order. The inspection sections on a model-year page are ordered by how many of that model’s complaints fall in the component groups a section covers, and each section names those groups and their counts. This feed reports only NHTSA’s top-level categories, so two sections covering the same category — the automatic transmission and the axles both sit under “Power train” — unavoidably share the same complaints, and the order between them carries no meaning. Finer sub-components exist in NHTSA’s bulk export and will separate these once it is processed.
• Ford F-150. NHTSA files F-150 complaints under body-style names (regular cab, SuperCab, SuperCrew); all three return the same pooled set of complaints for the model year, and that pooled set is what is shown. Its NCAP ratings, which genuinely differ by cab and drivetrain, are listed separately.

Failure mileage is not shown yet

The most useful reliability statistic in this dataset is the mileage at which a component failed — a median with quartiles says far more than a count does, and it is one of the few figures that is meaningful across models. That field exists in NHTSA’s full bulk export, but not in the API feed this site currently reads. Rather than estimate it, this site omits it. It will be added when the bulk data is processed.

What is not data

The inspection checklists are not computed from anything. They are written by a person — the site’s owner, who does this work on his own vehicles, including timing belts, clutches with dual-mass flywheels, injectors, axles and control arms — and they were reviewed and corrected before publication. The data decides only the order in which the checks appear on a given page.

Their wording is cautious on purpose. “Usually”, “most often” and “requires further inspection” are used instead of “means” and “is a sign of”, because a checklist that talks a buyer out of a sound car does more harm than no checklist.

No ratings, no scores, no rankings

This site publishes no reliability score, no star rating of its own and no ranking of models. There is no way to compute an honest one from data with no denominator, and a made-up number would be worse than none. The crash-test stars shown on each page are NHTSA’s own NCAP results, not ours.

Not advice, and not affiliated

This site is not affiliated with NHTSA, with any vehicle manufacturer, dealer or seller. Nothing here is professional or legal advice, or a substitute for a physical inspection of a specific vehicle by a qualified mechanic. Deciding whether to buy a car is yours alone.