The 3,000-mile oil change has gone the way of the dinosaur. What do I base this statement on given my staunch support of the 3,000-mile oil change for so many years? Today oils and lubricants are so much better compared to several years ago. Under normal driving conditions, viscosity breakdown (viscosity is the oil's ability to flow and lubricate) usually occurred at about 3,000 miles. The elements that cause deterioration of oil are heat, friction, chemical contamination, and oxidation. In recent years the petroleum companies, working hand-in-hand with carmakers, have developed stronger additive packages that address these factors. Today, oil is tougher and holds up much better under the rigors of the internal combustion engine environment.

Additionally, leaders in synthetic oil development like AMSOIL and Mobil One have come up with "super oils" in their full and semi-synthetic oil products.

Game Changer

About ten years ago GM introduced their OLM (Oil Life Monitor). This was a game changer for the industry. Essentially, GM told their customers to simply follow the dictates of the oil life monitor light on the dashboard to decide when to change the oil. Auto service departments across the nation raised a brouhaha that resonated in Automotive Heaven! Follow the dictates of a light? "Absurd" they cried! How can the vehicle itself know when to change the oil? Based on what? Ludicrous!

A few years later, Ford issued revised oil change drain interval recommendations: Every 7,500 miles for normal service, and 5,000 miles for severe service.

Again, traditionalists cried "Outrageous!" "Ridiculous!"

Cry as they may, I think that the "proof is in the pudding." How credible are the extended drain interval recommendations? How about this for credibility: The carmakers stand behind their warranty if a vehicle comes into the dealership with a failed engine and the owner/operator shows proof of regular oil change intervals according to factory-recommended extended oil drain intervals. End of story.

I think it would be wise to explain the GM OLM so that you understand how the system works, and consequently you will know you can trust it.

What is the GM OLM?

The GM OLM (Oil Life Monitor) is a system designed to calculate remaining oil life in your car's engine. The system is based on a computer algorithm that measures the serviceable oil life based on three criteria: crankcase temperature, combustion chamber events (work the engine does), and moisture (which is affected by environmental as well as internal temps and conditions). These three elements are what determine engine oil life. The system is able to calculate the serviceable engine oil life to within (+) or (-) 5 percent.

Can I trust the GM OLM?

Yes, GM engineers have tested the OLM extensively in both laboratory and real world settings since 1984. As a matter of fact, GM has so much faith in the OLM system that they have issued a new "Simplified Maintenance Schedule." Simply stated regarding oil changes, you follow the dictates of the OLM light.

The following is a quote from Peter Lord, the executive director of GM Service Operations:
"Customers don't have to worry about deciding when it's the best time to change their engine oil because our Oil Life System technology adapts to their driving conditions and habits, and determines the right interval. Since the new maintenance schedule is based on oil change intervals determined by this technology, customers can save time and cost." Finally, in the event that you file a warranty claim for the engine, the dealer will be able to determine that the oil changes were done according to the dictates of the OLM and therefore will be able to exonerate you from any denial of a warranty claim.

What are some benefits of the GM OLM?

Use of the GM OLM will often double or even triple the oil change interval for a typical vehicle when compared to the 3,000-mile oil change. The GM OLM will automatically adjust the oil change interval based on engine characteristics, driving habits, and the climate/environment 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 7,000 miles and as high as 12,000 miles (in some models). On the other hand, short trip driving in a cold climate may limit the oil change to 3,000 miles or less. In general, most people that drive a combination of city and highway find that the GM OLM will indicate an oil change every 5,000 to 6,000 miles. GM data shows the OLM extends oil change intervals without risks to the engine, saving you money in oil changes.

Savings realized using extended drain intervals

Say you drive 20,000 miles a year, which is above average. If you change oil according to the old recommendation of every 3,000 miles, you will spend on average of $210.00 annually for oil changes (based on $35.00 per oil change for regular oil). Following the extended drain interval for normal service recommendations for Ford at 7500 miles, you can expect to save $116.55 over a year. If you follow the dictates of GM's OLM, which comes out to approx every 6,000 miles, you can expect to save $93.45 annually.

Synthetic Motor Oil

Synthetic motor oil was first introduced by AMSOIL corp in 1972; Mobile One came on the scene about a year later. Good quality synthetic motor oil, while it is not inpervious to, is highly resistant to viscosity breakdown from heat, friction, oxidation, and chemical contamination. Why? Because of the purer base stock oil used as a foundation coupled to a vigorous chemical additive package added in the final formulation. Synthetic motor oil is more expensive than regular petroleum oil at the outset. But because of the extended drain intervals it's actually cheaper to use in the long run than regular petroleum oil. Typically, good synthetic motor oil has a drain interval of 7,500 miles for semi-synthetic blend and 20 – 25K miles for full synthetic motor oil. Much longer drain intervals have been recorded but I am not comfortable with going much beyond these intervals. Also, I am only quoting AMSOIL and Mobile One drain intervals, as these are the number one and two oils respectively. For more info about AMSOIL online go to: and for Mobile One:

Til' next time...Keep Rollin'

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