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Oil Change interval changed for 2015

27K views 7 replies 7 participants last post by  HairyReasoner 
#1 ·
My wife and I just picked up a new 2015 outback yesterday and I noticed after reading the maintenance manual that Subaru is now recommending 6000 mile oil changes for the 15 compared to 7500 mile oil changes on the 14. They also spec synthetic oil, 0w20. Oil tests have shown most synthetic oils to be good for 12k miles minimum. I just changed the oil on the 2014 outback we just traded in and with 8000 miles on it the oil was only slightly colored. Does anyone know why Subaru changed the oil change interval?
 
#2 ·
0w20 has been the spec for the FB engine since it debuted in 2011 in the Forester.

I'd say it is to address the oil consumption that has been experienced by some users, as most folks don't seem to know how to or that they should check their oil once in a while, no matter whether the vehicle is 2 weeks old with 14 miles or 32 years old with 350K miles.

Reduce the interval, less folks might run their vehicle out of oil if it has higher consumption.
 
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#3 ·
I actually wrote Subaru and asked what was behind the change. They emailed me a reply simply stating they "had no information" about why the oil change interval was changed. Of course, they have information--a change like that would have required study and review by engineers. It isn't made on a whim. Of course, there is a difference between having information and simply not wanting to say.


My Outback now has about 1300 miles on it. I have already checked the oil several times and not noticed any consumption. I haven't seen any reports of 2015's having a major oil consumption issue, so I'm hopeful it has been fixed.


It should also be noted that with the increasing use of 0W20 some manufacturers have been decreasing the oil change interval. Also more are requiring synthetic with shorter intervals. One guess I have is that in an effort for greater fuel efficiency, not only is thinner oil used, but the engines are running hotter. Initially, synthetic was sold as a way of increasing the oil change interval. But my guess is that now manufacturers are taking advantage of the synthetic properties to allow the hotter running engine while trading off the longer oil change intervals.
 
#4 ·
I think that AWDFTW nailed it. That's what I immediately thought when I heard that subaru reduced the oil change to 6K. My dealership sales guy for my 2014 recommended 5K, by the way, and the service guy recommended carrying an extra qt of oil in the back.

I'm using about half a qt in 5K and it's very steady usage.
 
#5 ·
Same reason "normal" BP numbers have been lowered. Nothing to do with overall health...everything to do with you "needing" professional service...$$$$
 
#6 ·
Why get hung up on the oil color?

One thing I don't understand is why you are mentioning the color of the oil and referencing it as an indication of oil health/usage.

That is not really a got indication, specially on a new engine that won't start to show signs of emery until several thousands of miles.
 
#7 ·
They cut the interval in half for the old turbo models. They've only trimmed it a little for these. I guess that's an improvement.

Harry, I expect you're right- they are depending on a few specific properties of synthetic oil for this power plant. But let's consider- essentially every engine which was a candidate for the extended run model was an engine designed to use ordinary petroleum lube.

Also, the military (original customer for synthetic oil in the 1940s) put priority on performance across a huge temperature spread. They didn't care how often they had to change it as long as it would let an airplane engine start at -50F and keep it going at 300F.
 
#8 ·
Finally got up to about 80 degrees where I live. Taking the Outback on a drive down the highway made me think the synthetic oil is required for its heat resistant properties. After about twenty minutes to a half hour of cruising mostly between 70 and 75 mph, my oil temperature was holding at 230 degrees. While I now that is short of the point at which conventional oil breaks down my understanding is that's pretty warm for the conditions compared to other vehicles. I'm a little concerned what the temp will go to when it's 100+ degrees or I head to the mountains somewhere. Good thing it is synthetic oil.

Perhaps the well known oil consumption problems of a short while ago were related to two issues: incorrectly finished piston rings and a hot running engine causing the oil to break down faster than typical. Once the oil breaks down it would pass the rings more easily. The piston ring problem was presumably fixed. Switching to synthetic oil helps the second problem although the extended drain advantage of synthetics is traded off.
 
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