Changing your oil is a necessary part of routine maintenance for any car. While most car owners can get away with a cheap $15.95 oil change from their local repair shop, BMW owners are often charged upwards of $100 at a reputable shop. My local BMW dealer charges $109.95 for an oil change special on the E39. To be fair, some BMW filters can be a little more expensive and most modern models require fully synthetic oil in larger than normal quantities.
Some of the best upgrades you can make to maximize the fuel economy of your BMW include: replacing the spark plugs, keeping correct tire pressures, and replacing old oxygen sensors. The oxygen sensors before the catalytic converters – located in the exhaust manifolds – play a large part in controlling the fuel mixture for the engine. When they have high mileage or have failed they no longer send a clear signal to the engine’s computer, at which point the computer defaults to a base line map designed to protect the engine. This default map is a rich fuel mixture (extra fuel) which causes sluggish performance and decreased fuel economy.