How we research and write
Engine oil is a safety- and money-sensitive topic, so we hold ourselves to a clear, repeatable standard. Here is exactly how our recommendations are made.
- Owner's manual first
- The exact vehicle manual is the final authority.
- Grade and specification
- Both requirements are checked separately.
- Sources and corrections
- Primary evidence, checked dates, and a public correction path.
Sources, in tiers
We weight sources by reliability and never let a weaker source override a stronger one.
Vehicle rows store this explicitly as sourceTier and structured
sources[] provenance.
| Source tier | Source | Role |
|---|---|---|
primary-oem | OEM owner's manuals, maintenance schedules, spec sheets | The only source that can originate a viscosity/spec recommendation |
secondary-manufacturer | Manufacturer service pages and official support material | Can corroborate a primary source, but does not replace the manual |
retailer-feed | Retailer selectors and product data feeds | Cross-check and product matching — never the origin of a claim |
licensed-dataset | Paid vehicle-spec datasets | Useful for coverage and conflict detection; still checked against primary evidence |
manual-curation | Human-entered rows from reviewed sources | Allowed only with recorded source fields and a review date |
sample | Fixtures used to test UI and validation | Always low-confidence, always noindexed, never a publishable recommendation |
Publication gate
How a vehicle oil record becomes publishable
- Identify the exact vehicle
Record make, model, year, engine and market before reading oil requirements.
- Capture primary evidence
Save the OEM manual URL, document version and exact page or section.
- Separate required fields
Record viscosity, specification, capacity, intervals, climate notes and official alternatives independently.
- Resolve conflicts
Compare stronger and weaker sources, record disagreements and never let a retailer override the manual.
- Approve and publish
A named review with a date is required before the route may become indexable.
Missing primary evidence, unresolved conflicts or pending review keeps the row provisional and noindex.
Confidence rating
Every car-specific entry carries a confidence level (high / medium / low) and
a "verified as of" date. A recommendation is only shown affirmatively when at least one
primary-oem
source backs it. Corroboration raises confidence; conflicts lower it. Low-confidence entries suppress the affirmative recommendation and route you to your
manual instead of guessing.
Conflict handling
If sources disagree, the row records the disputed field in conflicts[], keeps
or lowers confidence, and stays conservative until the conflict is resolved. Forum posts,
product listings, and generic fitment widgets can explain why owners are confused, but they
never raise confidence or override an owner’s manual.
How we write
- Answer first. Every page opens with a direct, two-sentence answer.
- Viscosity ≠ specification. We always separate the grade (e.g. 0W-20) from the required standard (e.g. dexos1 Gen3).
- Risk labels, not yes/no. Substitution questions get a clear label — safe, check manual, not recommended, or ask a mechanic — with the reasoning shown.
- Conservative by default. Where engine, year, or market matters, we say so and defer to the manual rather than overstating certainty.
- No "thicker is better." We correct common myths with sourced reasoning.
Verification & corrections
Pages carry a review date, and data entries a "verified as of" stamp. The public freshness manifest is available at /content-freshness.json. To locate primary OEM evidence, start with the owner's manual finder. Found something wrong? Use the correction link on a car page or the instructions on Sources & corrections — accuracy is the entire value of this site.