Can you mix different engine oils?

Mixing engine oils is a topic that stirs a lot of emotion. In an emergency, topping up with a different oil usually won’t do harm, but it shouldn’t become the norm.

An emergency top-up — is it allowed?

If the oil level has dropped and all you have in the boot is a different oil, it’s better to top it up than to drive on too low a level. Ideally choose an oil with the same viscosity and a similar specification.

What are the risks?

• Degraded performance of the additive package
• Incompatible approvals (a risk for the DPF)
• A change in the viscosity of the mixture
• Difficulty assessing the oil’s real parameters

A top-up on the road is a rescue. Once back home, it’s worth considering a change to a single, correct oil.

If you’ve mixed oils or don’t know what’s in the engine, the safest option is a full oil change — we’ll come to your address.