GMOLS is a computer-based algorithm that assesses engine combustion events, temperature, vehicle use, and other parameters to determine optimum oil change intervals. Oil changes are now called for when actually needed, instead of depending on generic time or mileage interval tables. Mild highway driving in a mild climate can yield change intervals of 7,000 miles (11,000 km) or more, and as high as 12,000 miles (19,000 km) for some vehicles. Short trip driving in cold weather may reduce intervals to 3,000 miles (5,000 km) or less. Most people driving a combination of city and highway will likely see intervals of about 6,000 miles (10,000 km).
When GMOLS determines that an oil and filter change is needed, the driver is notified by a Change Oil message on the instrument panel (fig. 10). Oil should be changed within 600 miles (1000 km).
TIP:The Oil Life System must be manually reset when the oil is changed.
How the Oil Life System is Related to Maintenance
The previously complicated, traditional normal/severe maintenance schedules required about 25 pages of explanation in the owner’s manual. The new simplified maintenance schedules can be explained in about 3 pages (see TechLink May 2003 for a summary).
All routine maintenance is grouped into one of two schedules, Maintenance I and Maintenance II. These services should be performed alternately, each time the GMOLS message is displayed.
Benefits of GM Oil Life System and Simplified Maintenance
Benefits for the customer -- GMOLS takes the guesswork out of when oil changes are needed; the owner doesn’t have to keep track of anything. With maintenance intervals now aligned with oil changes, the customer can conveniently have both done during one service visit.
Benefits for the dealer
Because of the typically extended oil change intervals, the customer may come back less frequently. But when they do come back, it’s for more services. The inspection and service points of both Maintenance I and Maintenance II are thorough, and are intended to keep the vehicle in good working order. They also give the technician the opportunity to locate, identify and recommend other needed services.
Benefits for the environment
With GMOLS now installed on upwards of 20 million vehicles, if it’s used as intended, it can save almost 100 million gallons of oil in 5 years. And remember that every quart of oil poured into an engine eventually has to be drained out and properly disposed of.