Hello, I brought my Mondeo 99 year of construction to the ATU because of an oil change. On the bill now it says: ATU OEL What kind of oil is that? Then they filled in 5W-40 partly. Does that do anything at all? Is this ideal for a Mondeo? According to Castrol, should I use 5W-30. Is this better for a Mondeo? Thanks and greeting Johannes