What does 5W30 mean? Oil viscosity explained
What does 5W30 on an oil pack mean? We decode the viscosity markings so you know which oil suits your engine.
What does 5W30 mean? Oil viscosity explained
4 min readThe marking 5W30 is an oil viscosity grade according to the SAE standard. Although it looks mysterious, it tells you exactly how the oil behaves when cold and when hot.
What do the individual symbols mean?
- 5W — the oil’s cold behaviour (W = Winter); the lower the number, the better the cold start
- 30 — the oil’s viscosity at high engine operating temperature
- The higher the second number, the thicker the oil when hot
Why does it matter?
Oil that’s too thick when cold makes starting harder and takes longer to reach engine parts. Oil that’s too thin when hot protects worse against friction. That’s why viscosity is matched strictly to the manufacturer’s recommendations.
5W30 and 5W40 are often confused — they differ in their hot behaviour. Find out when to choose which oil.
During a mobile oil change we’ll match the right viscosity to your engine and operating conditions.
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