What does 0W-20 mean? Oil viscosity grades explained
In 0W-20, the “0W” is the oil’s cold rating (W stands for winter) and the “20” is its rating once the engine is warm. A lower first number means the oil flows more easily when cold. The grade your engine needs is in your owner’s manual, and it can differ between engines in the same car.
What do the two numbers mean?
- The number before W rates how the oil behaves when cold, under the SAE J300 standard. 0W flows better at low temperatures than 5W.
- The number after the dash rates how the oil flows at operating temperature. A 20 is thinner when hot than a 30.
- Multigrade: a 0W-20 behaves like a thin 0W oil when cold and like a grade-20 oil when warm (Castrol: what is 0W-20).
Can two engines in the same car need different oil?
Yes. The 2021 Chevrolet Malibu manual says to use SAE 0W-20 for the 1.5 L turbo engine and SAE 5W-30 for the 2.0 L turbo engine. Check which engine you have first: see Which engine and body style do I have?
Is it OK to use a different grade in very cold weather?
Only if your manual says so. The same Malibu manual allows SAE 0W-30 “in an area of extreme cold, where the temperature falls below −29 °C (−20 °F)” for easier cold starting (2021 Malibu manual). Other manuals list only one grade.
Does the brand or specification matter too?
The grade is only part of it. Many manuals also name a specification or approval the oil must meet. The Malibu manual asks for full synthetic oil meeting GM’s dexos1 specification, and Nissan’s 2022 Rogue manual recommends 0W-20 SP, where SP is an API service category. Look for both the grade and the specification on the bottle.
For how much oil to add, see Oil capacity: with filter, without filter and total fill.