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Should I follow my car's service schedule or listen to the dealer?

My 2012 Ford Focus' service manual says this vehicle has the Intelligent Oil Life Monitor (IOLM) system which will indicate when an oil change is required. Depending on the type of driving, it could last up to 16,000 km or a year. But the Ford service advisor is insisting that I change oil at every 8,000 km or 6 months, whichever comes first. The car has 15,400 km and the service light has not come on yet. What should I do, follow the Ford service rep or the manual?

– Shabbir, Mississauga

Your dealer's advice for an oil change every 8,000 km comes straight from the owner's manual – for when to change the oil if the monitoring system is broken.

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"The dealer would be the best to evaluate the vehicle and assess if an oil change is required," said Ford spokesperson Christine Hollander. "Something could be wrong with the system."

The 2012 Focus owner's manual doesn't have an oil change schedule. It says to change the oil within two weeks (or 800 km) of getting a dashboard message saying "engine oil change due" or "oil change required."

And, yes, it says that you could go 16,000 km, or a year (whichever comes first) before getting that message, depending on how you drive.

So how does the system know when your oil needs to be changed?

"It doesn't monitor any quality of the oil," says Pete Misangyi, supervisor of Ford's fuels, lubricants and electronic throttle control monitor calibration section. "It infers when an oil change is needed based on how you operate the vehicle."

The system decides how hard you've been driving based on engine oil temperature, engine RPMs, mileage and time, Misangyi says.

"For example, if you're idling for a long time, it will add demerits," Misangyi says. "If you tow a trailer, you'll have higher oil temperatures."

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If a year has passed and you haven't hit 16,000 km – or driven hard enough to warrant an earlier oil change – the system decides it's time for a change.

The manual says to reset the system after every oil change, so it knows to start monitoring again from scratch. If it gets reset early, or if it's not working at all, the manual says to change oil every 8,000 km or 6 months.

So, assuming your dealer has examined your car, he may have decided that you need an oil change sooner than recommended, Ford says. Or he may think the system is broken. Ford says to listen to your dealer.

Changing it earlier than needed won't hurt – but it will cost you more. Wait too long and it will turn to sludge and could seize up your engine. And even if you're not driving much and vehicle is mostly sitting, oil can break down over time.

But, if you're using the recommended oil, a year or 16,000 km between oil changes isn't unrealistic, Misangyi says.

"Todays oils last a lot longer," Misangyi says. "Every three, four, or five years we see a significant improvement in the quality of oil."

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The Automobile Protection Association (APA) says engine oil is supposed to last a long time, normally.

"We've seen fleets running 20,000 km between oil changes using synthetic oil," says APA president George Iny. "The problem is that few consumer vehicles are operated under normal service in Canada during the winter, when frequent short trips with a not fully-warmed-up engine are the norm."

Most car makers suggest a more frequent oil change schedule for severe use in Canadian winter driving.

Iny says the dealer's advice for an oil change at 8,000 km or six months doesn't necessarily sound slippery – especially during the winter or if you're driving a car that's especially thirsty for oil. He says dealers and shops don't usually make much money on oil changes because they have to keep prices low to compete with oil change places.

"For engines with a known weakness such as several VWs, Toyota's 3-litre V6, Chrysler's 2.7-litre V6, BMW's inline 6 cylinder, Mazda's 2.3-litre and others, the recommendation from the service advisor is prudent," Iny says. "It also strikes us as a good, conservative, recommendation for winter driving conditions, especially when you consider that many consumers no longer check the oil level between changes."

Consumer Reports magazine says you don't have to get oil changes and scheduled service done by your dealer – the warranty should be valid no matter where you get the service done, as long as it's done according to the schedule.

What do you think? Leave your comments here.

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