Q: What oil should I use in my 04 Audi A4 3.0L V6 Quattro S Line, either 5W30 or 0W40-10W40?

Viscosities of 5W-40, 5W-30, 0W-40, and 0W-30 are all specified for your model, the main selection criteria being the ambient temperature you are operating in. If you are in Alaska, use 0W-30. If you are in the southeastern desert, use 5W-40. As important are the certifications of the oil which must meet or exceed Audi’s requirements as specified in your Owner’s Manual in the maintenance section. If you desire, a YourMechanic certified mechanic can change your oil and filter right at your location and such service will include the correct viscosity oil based on your location. If you have further questions or concerns, do not hesitate to re-contact YourMechanic because we want you to make the most of your repair dollars and help you to get the best possible results.