Flexible Service System

Reprinted from the 500 Section Star,  Steven Rae, Editor

        Change the oil at 20,000 miles? Heresy you say? Certainly just a few years back it indeed would have been heresy to propose such extended oil change intervals.  Starting in the 1998 model year and in keeping with the global need for conservation of nonrenewable resources,  Daimler-Benz developed a system to calculate when the oil needed to be changed, and added a warning system on the instrument cluster to remind the driver. Just how does this system work and of course the big question that keeps me up at night, "How often should I change my oil?"

In doing research on oil quality throughout it's "life" in the engine, Daimler Benz discovered that the breakdown in oil correlated directly with it's increased ability to conduct an electric current, or conversely, a decrease in the dielectric constant (less resistance to electrical current flow).  They also determined that such driving habits as making frequent short trips, driving at high speed, and failure to replenish low oil levels can contribute to faster oil breakdown and the need for more frequent oil changes. Drum roll please....And so was born the Flexible Service System or FSS.  With inputs from the oil sensor,  coolant temperature sensor, engine control module and tachometer, the computer calculates the optimum interval for the next oil change and signals the driver accordingly. The exception to this system,  I believe, is the 4-cylinder cars which do not have the oil sensors but utilize all other inputs to the computer. In practice, average oil change "recommendations" are between 10- 12,000 miles, but, as always, your mileage may vary.

Does the system work? Probably but it is still too early to tell. Can an owner change the oil sooner than calculated by the FSS? Absolutely. Can the FSS be reset if more frequent oil changes are done? Certainly, and the instructions are in the Owner's Manual. What's the bottom line? If you are an average driver (and I doubt ANY of our Section members are average) then the FSS frees you from worry about when to change the oil, but if you would prefer to change the oil more frequently, then by all means do so and worry about something else like eliminating chinch bugs from your lawn.

If you wish to delve further into this topic, check out page 70 of the Jan/Feb '99 edition of the Star magazine.