Neutral · manual-first · no brand bias
Understand the right engine oil for your car.
We translate your owner's manual and OEM specifications into plain English — what the viscosity numbers mean, how grades compare, and what's safe for your specific car, climate, and driving. Specifications first, products second, always confirm against your manual.
Viscosity is not the same as specification
Viscosity (the grade)
0W-20
How thick the oil is — cold-start flow and hot-temperature protection.
Specification (the standard)
dexos1 Gen3
The performance standard your engine requires. Match both — not just the grade.
Start here
- Learn the basics What viscosity is, in plain English.
- Viscosity grades What 5W-30, 0W-20, 10W-40 and the rest mean.
- Compare grades Neutral side-by-side comparisons — no brand bias.
- Can I use… Substitution answers with a clear risk label.
- Specifications API, ILSAC, ACEA, dexos and OEM approvals.
- Guides Intervals, climate, high-mileage, turbo and more.
Popular questions
- 5W-30 instead of 0W-20? Generally you should not substitute 5W-30 for 0W-20 unless your owner's manual lists 5W-30 as an acceptable alternate. Engines that specify 0W-20 are designed for the thinner oil, so the thicker grade can reduce fuel economy, hurt cold-start flow, and may affect your warranty.
- Is thicker oil better? Is thicker engine oil better for your car? The short answer is no — the right oil is the grade your manual specifies, not the thickest one.
- What happens if you use the wrong oil? What happens if you use the wrong motor oil? It depends — the wrong viscosity and the wrong specification carry different, often manageable, risks.
- 0W-20 vs 5W-30 Different cold flow and different hot thickness — follow the grade your manual specifies, not the heavier one.
- 5W-30 vs 5W-20 Same cold rating, different hot thickness. Follow the grade your manual specifies; do not pick by "thicker is safer."
- What is oil viscosity? What is motor oil viscosity? A plain-English guide to the grade numbers, the W for winter, multigrade oils, and why viscosity matters.