0W-16 vs 0W-20 Oil: What the Numbers Mean and Why It Matters

Last updated: August 2026

Modern Toyota and Honda engines increasingly specify ultra-thin oils like 0W-16 where older engines used 0W-20 or 5W-30. The numbers aren't marketing — they describe how the oil flows, and using the wrong grade can affect fuel economy, wear, and warranty coverage.

Reading the grade

In 0W-20, the first number followed by W (for winter) describes cold-start flow — 0W flows fastest when cold, protecting the engine in the critical seconds after startup. The second number is the viscosity at operating temperature: 16 is thinner than 20, which is thinner than 30.

Why newer engines go thinner

Engines like Toyota's A25A (Camry, RAV4) are built with tighter tolerances and oil passages designed for low-viscosity oil. Thinner oil reduces internal friction, which is worth real fuel economy — that's why a 2018+ Camry specifies 0W-16 while the 2017 model used 0W-20. See the per-year breakdown on our Camry oil by year table.

Can you substitute?

Follow the owner's manual first. Many manuals list an acceptable alternative (for example, 0W-20 if 0W-16 is unavailable, with a return to the specified grade at the next change). Going thicker than the manual allows on a modern low-viscosity engine is not an upgrade — it increases drag and can starve tight passages. Check your exact engine's requirement on pages like 2022 Civic oil capacity.