Many vehicle manufacturers (including Porsche, BMW, Audi, Volkswagen and Mini) have extended their oil change intervals in an attempt to reduce maintenance costs to the vehicle owner, and as a result have run into trouble with repairs as a result. Audi, Volkswagen (and even Toyota) have suffered a rash of warranty claims on some of its engines due to oil sludging because the owners were not changing their oil often enough or using the correct grade of oil. Apparently, their recommended service interval of 10,000- 15,000 miles wasn't often enough. Unfortunately for many, problems related to neglected maintenance may not surface until after the car's warranty expires. Extended oil change intervals are based on "ideal operating conditions," not the type of short-trip, stop-and-go driving that is typical for most motorists. Consequently, we recommend you follow the "severe" service maintenance schedule rather than the "normal" schedule and have your oil and filter changed every 3,000 miles and 5,000 miles for conventional and synthetic oil respectively.