What’s in an owner’s manual? Data from 1,662 manuals (2006–2026)
We copy maintenance specs out of owner’s manuals for a living: 1,662 of them so far, from 13 makes (Acura, Buick, Cadillac, Chevrolet, Ford, GMC, Honda, Hyundai, Lincoln, MINI, Nissan, Tesla, Volvo), model years 2006 to 2026. Along the way the manuals tell a story about how cars have changed, and about what they do and don’t tell owners. Every number below is counted from the specs on this site, and each spec links to the manual page it came from.
Key findings
- 0W-20 took over. 67% of 2020–2026 manuals that name an oil grade list 0W-20, up from 11% in 2010–2014. 5W-20 went the other way: 33% to 5%.
- Most manuals don’t print your tire pressure. Only 35% do. None of the Buick, Cadillac, Ford, GMC, Lincoln manuals in our set print it; they point you to the door-jamb label. Acura, Hyundai, Honda, Nissan manuals nearly always do.
- Your key fob probably takes a CR2032: 78% of manuals that name a fob battery list one.
- LED headlights went mainstream: 60% of 2020–2026 manuals that list a low-beam bulb mention LED low beams, against 3% in 2010–2014.
- The A/C refrigerant changed: 85% of 2020–2026 manuals that name a refrigerant list R-1234yf; 0% did in 2010–2014.
Motor oil: the shift to thinner grades
Share of manuals in each period that list each oil grade. A manual can list more than one (by engine, or a cold-weather alternative), so the bars don’t add up to 100%.
2010–2014 (385 manuals)
2015–2019 (479 manuals)
2020–2026 (502 manuals)
Thinner oils help fuel economy, and engines built for them are designed around their flow. Use the grade your manual names: see 0W-20 vs 5W-30.
Who prints the tire pressure in the manual?
Share of each make’s manuals (in our set) that print a recommended road-tire pressure. The rest refer you to the Tire and Loading Information label on the driver’s door jamb, which every passenger vehicle has.
Whichever source you use, set the pressure cold. More in Finding the right tire pressure.
Key fob batteries
Of the 936 manuals that name a key fob battery:
Some manuals list two (a smart key and a remote).
Check yours in Key fob battery by vehicle; the difference between the two most common is in CR2032 vs CR2025.
Headlights and air conditioning
Shares of manuals that list a low-beam bulb, and of manuals that name the A/C refrigerant.
More: Halogen or LED headlights and R-134a vs R-1234yf.
Brake fluid
Of the 171 manuals that name a brake fluid grade:
See DOT 3 vs DOT 4.
Oil capacity
Across 1,851 oil-capacity figures (with a filter change), the median is 5.7 quarts. The smallest we’ve seen is 3.5 qt (2016 Honda Fit); the largest, 14.6 qt (2010 GMC TopKick, a medium-duty truck). Full list: Oil capacity by vehicle.
The warning lights manuals explain most
From the warning-light pages of the newest manual for 196 models. These are the lights explained most often, not every car’s full set.
What each one means: Dashboard warning lights.
How we counted
Each of the 1,662 manuals is one make, model and model year, downloaded from the manufacturer. Specs were read from the manual pages with AI assistance and kept only when the value and a quote were found on the cited page; anything that failed that check isn’t counted. Percentages are of the manuals that list that spec, so a manual that doesn’t mention, say, brake fluid isn’t counted as DOT 3 or DOT 4. Our set leans toward the makes whose manuals are published as PDFs (Acura, Buick, Cadillac, Chevrolet, Ford, GMC, Honda, Hyundai, Lincoln, MINI, Nissan, Tesla, Volvo), so it isn’t a sample of every car on the road.