GM Oil Life Monitor System Frequently Asked Questions How does the system work? The GM Oil Life Monitor System is not a mileage counter. It is actually a computer based software algorithm that determines when to change oil based on engine operating conditions. There is no actual oil condition sensor. Rather, the computer continuously monitors engine-operating conditions to determine when to change oil. Over the years, millions of test miles have been accumulated to calibrate the system for a variety of vehicles. The system was first introduced in 1988 and is now on more than 10 million GM vehicles. How do I operate the system? The GM Oil Life Monitor System is very easy to use. First, refer to the vehicle owner’s manual for a description of the specific ‘change oil’ message and the instructions for resetting the system. When the vehicle has been driven the appropriate miles, the ‘change oil’ message will be illuminated on the instrument panel or driver information center when the vehicle is first started. An oil change should be done within two fuel tank fillups from when the message was first displayed. Immediately after the oil has been changed, the system must be reset. After resetting, the ‘change oil’ display will no longer be displayed after engine start up. I change my oil every 3000 miles, so of what use is this system? You can continue to change your oil every 3000 miles if you so choose, but remember to reset the system after changing the oil or you will get a false “change oil” message. However the GM Oil Life Monitor System will allow you the ability to extend the mileage between changes without harming your engine. This will save you time and money as well as helping to protect the environment by minimizing the amount of used oil. Do I have to use special oil? The GM Oil Life Monitor System is calibrated for use with standard “Starburst” mineralbased automotive engine oil. Synthetic oils are not required except for the Corvette. Make sure to read the owner’s manual and select the viscosity and oil grade that is correct for your engine. Any oil selected for use should carry the ILSAC “Starburst”. How many miles can I expect to go between oil changes when using this system? The beauty of the GM Oil Life Monitor System is that it will automatically adjust the oil change interval based engine characteristics, driving habits and the climate in which the vehicle is operated. For instance, mild highway driving in a warm climate will maximize the interval between oil changes. Depending on the vehicle, this could be in excess of 7000 miles and as high as 12,000 miles. On the other hand, short trip driving in cold a climate may limit the oil change to 3000 miles or less. In general, most people that drive a combination of city and highway schedules find that the GM Oil Life Monitor System will indicate an oil change every 7500 to 8500 miles.