Can You Trust Your Car's Oil Life Monitor Feature?

When it comes to car maintenance, nothing sparks as much debate as how often you should change your motor oil. The consensus today is that for the general public driving to and from work daily and the occasional family road trip, it should be every 3,000 to 5,000 miles despite car makers sticking to their recommended every 10,000 miles…and sometimes further.

The Automaker's 10,000-mile Intervals

The accusation (with some merit) is that the car maker recommendations are based on the minimum maintenance you need to do to make it to the end of your warranty period. You can figure out for yourself why this is beneficial to the Automaker but not so much to the general public.

To be fair, however, automakers are not just looking at the profit margins but are also influenced by what they believe consumers want. Hence the marketing sell that with the new and improved motor oil and other fluids of today, cars are low maintenance with more abusable engines, sealed transmissions with "lifetime" claims, and cooling systems that never need a change of their coolant. Hogwash!

In other words, most car owners do not want to be bothered with their car maintenance and so the automakers are giving them what they want. Again, this is beneficial to the Automaker but not so much to the general public.

Technically, How Often Does Your Car's Motor Oil Need to Be Changed?

Chemically, the most accurate answer to the question is that it depends on how your car is driven: Long drives or short drives? Hot temperatures and dusty conditions or normal to cooler conditions with less dust in the air? Does your car sit parked for weeks at a time, or is it driven daily?

The point to these questions is that all of the above chemically affect how long your motor oil truly lasts. In fact, it can be as bad to not change your oil more often if it is driven only on short trips infrequently and generates less mileage than it is to go further between changes than recommended while racking up a significant number of miles.

In other words, only an oil analysis can tell you for sure what the state of your motor oil is at any point in time.

But what about oil life indicator features in modern cars? Do they really work?

What is an Oil Life Monitor (Indicator) Feature in Cars?

An oil life indicator is a feature found in some modern car models that monitors the condition of the engine oil and informs and advises the driver when it's time for an oil change rather than relying on your car's odometer and/or the date you last had your oil changed.

This "advice" from the algorithm is based on multiple factors that takes into consideration mileage and time, driving conditions, engine temperature, excessive RPM and excessive driving, and whether the vehicle is used for towing.

Reputedly, the oil life indicator provides a more accurate assessment of when the engine oil is losing its effectiveness, often displayed as a percentage (e.g., "Oil Life 10%"). When the percentage gets low, the car will alert the driver that an oil change is necessary.

But does this really work toward ensuring your car's engine is protected with the optimal and potentially fluctuating interval of oil changes the algorithm suggests?

Can You Trust Your Car's Oil Life Monitor?

That was one of the questions posed by Lake Speed, the host of The Motor Oil Geek YouTube channel, who reveals what he found when testing what algorithms are saying (predicting actually) compared to what the oil analysis results say.

Follow along with the host and discover:

• How the oil life indicator algorithm was created.
• How the ECU supplies the data the algorithm needs.
• Why oil-to-fuel contamination is so important with each engine cycle.
• Why operation temperature matters.
• How some car owners prematurely degrade their motor oil.
• What does motor oil analysis say about the oil life indicator feature?

In case you do not have time to watch the video, a summary is provided below to answer the question of whether you can trust your car's oil life indicator.

The Accuracy of OIL LIFE Indicators Revealed!

Video Summary Points You Need to Know

The take-home message from the host's oil analysis results is that the oil life indicators on some GM, Cadillac, and Ford models are actually on the conservative side of when it is time to change your motor oil based on the amount of predicted life the algorithm states on your dash or screen.

"This tells you how far you can go…safely," states the host after looking at the numbers revealing the actual condition of the oil with respect to a 9% oil life reading from the indicator feature, adding that when looking at the wear indicators in the analysis that the engine wear was actually well below the specs recommended for motor oil.

Related article: Common Mistakes When Analyzing Your Car's Motor Oil

"As an oil analyst, I can tell you if you have a GM car or truck with this oil life indicator, you don't even need used oil analysis to figure out how far you should go on your oil change interval…I think this is conclusive proof that you can trust the oil life indicator to tell you when it is time to change your oil," states Lake.

Here are a few useful articles related to your car's motor oil:

• The Truth About Motor Oil Additives
• The Secret Motor Oil Companies Don't Want You To Know
• Walmart Engine Oil Showdown You Do Not Want to Miss

Timothy Boyer is an automotive reporter based in Cincinnati. Experienced with early car restorations, he regularly restores older vehicles with engine modifications for improved performance. Follow Tim on Twitter at @TimBoyerWritesfor daily news and topics related to new and used cars and trucks.

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