The difference between 5W30 and 5W40 oil

The choice between 5W30 and 5W40 keeps many drivers awake. Both oils behave identically when cold, but differ in viscosity at high temperature.

What is the difference?

The number after the letter W describes the hot viscosity. 5W40 is slightly thicker at high temperatures than 5W30, which can be beneficial for more heavily loaded engines or those with higher mileage.

When 5W30, and when 5W40?

• 5W30 — modern engines, lower consumption, required by many approvals
• 5W40 — older engines, heavily loaded, higher mileage
• The manufacturer’s approval always decides, not viscosity alone
• Don’t change the class on your own without checking the recommendations

A thicker oil doesn’t always mean better — what counts is compliance with your engine’s specification.

Not sure which class to choose? We’ll advise and change the oil with call-out to your address.