What type of oil do I use for Ford focus 2010 diesel 40000 mile age?

For a 2010 Ford Focus diesel with around 40,000 miles, it's recommended to use a low ash, fully synthetic oil that meets the specifications of ACEA C1 or C2, such as 5W-30 or 5W-40 viscosity. Always check your owner’s manual for the specific oil requirements and specifications, as well as any recommendations for oil change intervals. Using the correct oil will help maintain engine performance and longevity.