Oil change interval: Use the manual's, or the car computer's, or oil manufacturer's recommendation?

[JEDI]

2015 Mazda3i automatic, 95k miles

1) i drive mostly highway so the manual recommends every 7500 miles.

2) Car computer can also calculate when to change my oil based on my driving habits. (stops, starts, acceleration rate, engine RPM, etc)
Last time i didnt change the oil till the car recommended it, which was about 11k miles.

3) I just bought Mobil 1 Extended 0w20 synthetic, which says it lasts 15k miles.

All of my oil changes are done by me and I used whatever name brand 0w20 that was cheapest at that time after rebate (Valvoline, Quaker, Penzoil) but i used Walmart brand oil filters.

This time i bought Mobil 1 Extended with a Mobil 1 oil filter because the combo was on sale for $19 after rebate.

I'm tempted to do the 15k miles between oil changes, mainly because of the better oil filter.
What do you think?

Which interval would you do?
Why?

 

[jlee]

I would do it when the car says to - oil is cheap

 

[DooKey]

I change the oil according to the manual or the oil change sensor. Wife's Murano doesn't have a sensor and my Silverado does.

 

[herm0016]

It generally not a "sensor" its a calculation based on engine load, temperatures miles, etc. Just FYI. We follow the indicator on the volt, and I do my pickup every 5 or 6k miles. Cheap insurance. We live in a dusty and dry place, tow, drive in the mountains, etc.

 

[mindless1]

Car computer or otherwise, roughly 10K mi max. Extended oil changes of 15K mi or more are not well suited to high revving little engines. Granted high hwy miles are easier on it.

Considering you are at near 20K mi/year on a 5-6 year old vehicle, it could make sense to just do an oil change twice a year, spring and fall.

 

[UsandThem]

The only true way to know if you can go longer than the recommended change intervals would to send your used oil in for analysis (at least a few times). And those cost money. It is likely you could run the Mobil Extended oil for 10,000 without worrying about it too much, but since there are so many different variables (engine, driving style, environment, etc), that is not a guarantee.

Or you can just change it every 7500 miles with whatever oil is on sale/mail in rebate. I usually buy several oil changes worth of oil say when Mobil/Pennzoil does their annual rebate, or if I need more oil for whatever reason, you can get something like Walmart's Super Tech 5 quart synthetic for under $15.

 

[BonzaiDuck]

I'm less familiar with (not familiar with!) the newer cars of the last ten or even more years. They're using lower viscosity oil -- 20W. The spec intervals for changes are different -- and greater. Older cars, like my 25-year-old Trooper, had an interval of 3,000 miles, and I'm well aware of this 7,500 mile spec on the newer models.

But I don't care how new it is, if you're doing your own oil changes. I posted a thread a couple months ago discussing "oil drain valves" by Fumoto and Valvo-Max. If you change your own oil -- get one! No fuss; no mess. only requires a waste-oil container, perhaps with Fumoto a plastic tube to fit the nipple, and you'll never spill a drop. With that, you could change your oil every 1,000 miles without any effort at all, but it would be uneconomical.

However, the drain valves allow you to take a one-ounce sample of oil just to look at it. If it looks as though it's getting darker, you can change it as you like. The dipstick doesn't really allow you to do that. Harder to tell the difference in oil color just from a small smear on the dipstick.

Also, you can change the oil more frequently, and replace the filter at every other oil-change. If there's no work or strain or mess, you could change your oil to the limit of it becoming needless waste of money. All the waste oil is recycled. So you stay "green", even with a bigger leak from the green in your wallet.

But the factory spec of 7,500 miles -- whatever it is -- that's good enough, certainly. To some limit, more frequent oil changes are marginally better than less frequent.

 

[manly]

I think my official OCI is 10k miles/1 year. I do the change annually, which is at about 7500 miles give or take.

OP does his own oil changes? I don't see a great benefit in running extended OCI. Your full synthetic oil and good filter are reasonably cheap insurance. In your case, I'd probably stick to the manual's guidance or at most go up to 10k miles between changes.

 

[BonzaiDuck]

I think my official OCI is 10k miles/1 year. I do the change annually, which is at about 7500 miles give or take.

OP does his own oil changes? I don't see a great benefit in running extended OCI. Your full synthetic oil and good filter are reasonably cheap insurance. In your case, I'd probably stick to the manual's guidance or at most go up to 10k miles between changes.

I most certainly agree, given the fact that my 95 Trooper is 25 years old and can use 10W-30 and 10W-40 depending on weather. You can get a 5-qt container of generic (O'Reilly's for instance) full-synthetic for maybe $23. If you do the work yourself, and if especially you make it convenient with a drain valve, you could do three or four oil changes a year -- no sweat. Let's suppose you only do one. Four would cost you maybe $69 extra per year. Paying a mechanic and shop to do your change would be a minimum of maybe $50 and full-synthetic might make it $70 or $80.

I say "Do it! Doooo it!"

Troubleshooting my Trooper in the aftermath of the Little Repair Shop of Horrors and its Mechanic from Hell, I gave it three oil changes in January. The second one was requisite to installing the drain-valve -- which was an afterthought following the first change, and a need to deal with a leaky drain plug. After replacing vacuum hoses, reconnecting the fuel pressure control valve to the intake manifold and cleaning sensors, I did it a third time. At the moment, I'm headed toward 1,000 miles.

I may change the oil at 2,000 -- I can't say for sure. But at 3,000 miles per year on the odometer, the extra expense and trip to Autozone for recycling doesn't count for much. I'll save my mechanic for special jobs. I'll even pay him extra in the fall to do a once-over inspection of the vehicle to find problems or see if he can't improve something.

Some of the newer filters made for full-synthetic and costing between $11 and $15 are rated for 11,000 miles. So? Change it every 5,000 or 6,000. It's not going to make you file for bankruptcy, or rob you of those extra enchilada dinners . . . .

 

[WackyDan]

The computerized indicators have gotten way better. On our 2005 it was mostly just a mileage counter.

On my 2012 F-150 the oil life sensor is more advanced. Manual calls for oil change interval potentially between 7500 and 10,000 miles on an 8 quart capacity. I only put about 5k miles a year on it and up to half of that is towing. I've never been able to go the full 7500 min interval as either I reach the year mark and change it anyway or I've towed so much that the sensor is getting down to about 15%. I did have an oil analysis done which did point to being able to go a little longer, but at 5k miles a year I'm changing it anyway.

Our 2018 Volt is a lot more advanced and only requires changes once every two years or when the sensor and computer tell you to.

My suggestion to you is to have an oil analysis done. I did that on our old 2005 Malibu and was able to comfortably add a couple thousand miles to the interval on regular conventional oil... and likely could have gone a bit longer.