Why not run synthetic? There's almost no reason not to.
That being said - the perfectly maintained engine experiencing significant oil induced failure rates due to oil choices is a laughable unicorn for non-turbo Subaru's. It simply doesn't happen.
Practically speaking it doesn't matter - you can run 300,000 miles on conventional oil all day long. Never apply that to turbo's, the oil is a heat soak for the exhaust and turbo heat.
But conventional requires more frequent change intervals, and synthetic is great, cheap, and widely available and works out to the same price (more expensive but fewer change intervals), so there's almost no reason not to do it unless you like doing more oil changes or don't want to add more expensive oil on an engine using oil which presumably wont' be a 2018.
An average daily driver will have no issues with conventional oil if:
1. do not go over change intervals at all
2. do not let the oil get low
3. do not overheat the engine
Keep in mind it's less forgiving and don't neglect those things. The H6 chain tensioners aren't going to thank you if you neglect those items, rod bearings will be next.
Those items listed above are the actual oil induced failure modes of your engine that happen plenty of times. That's the important data. If you want to choose synthetic to give you a very slight edge over those issues, then by all means do it, it's great and cheap, and i'm not sure why you wouldn't do it. If you want to choose conventional and plead on mamma's grave you won't neglect those items above - you'll be fine.
there are countless H6's with hundreds of thousands of miles on conventional oil, there's not some magic thing that happens to some engines and not others or some owners and not others. "i run 300k on all my vehicles with _________________" (insert favorite boutique brand, cheapest/on sale oil, or anything in between) is common and routine - all because it doesn't matter. choice makes insignificant differences for average daily drivers.
the many thousands of Subaru's making hundreds of thousands of miles over the decades make easy quantitative practical data. many of these run conventional without issues and synthetic without issues. and then if you dial in on the ones that do have issues, which *SHOCKER ALERT* does include synthetic oil users - you'll quickly learn the causes of oil induced failures and it's never oil choices. plenty of synthetic engines are blowing up too, but it's not the oil. it's poor maintenance.
* Usually it's just owners neglecting oil changes and leaks. i can't exaggerate how common it is. i can literally buy a blown subaru engine weekly that was run low on oil. who cares what oil you use if you're going to do that?
happens.
all.
the.
time.
That being said - the perfectly maintained engine experiencing significant oil induced failure rates due to oil choices is a laughable unicorn for non-turbo Subaru's. It simply doesn't happen.
Practically speaking it doesn't matter - you can run 300,000 miles on conventional oil all day long. Never apply that to turbo's, the oil is a heat soak for the exhaust and turbo heat.
But conventional requires more frequent change intervals, and synthetic is great, cheap, and widely available and works out to the same price (more expensive but fewer change intervals), so there's almost no reason not to do it unless you like doing more oil changes or don't want to add more expensive oil on an engine using oil which presumably wont' be a 2018.
An average daily driver will have no issues with conventional oil if:
1. do not go over change intervals at all
2. do not let the oil get low
3. do not overheat the engine
Keep in mind it's less forgiving and don't neglect those things. The H6 chain tensioners aren't going to thank you if you neglect those items, rod bearings will be next.
Those items listed above are the actual oil induced failure modes of your engine that happen plenty of times. That's the important data. If you want to choose synthetic to give you a very slight edge over those issues, then by all means do it, it's great and cheap, and i'm not sure why you wouldn't do it. If you want to choose conventional and plead on mamma's grave you won't neglect those items above - you'll be fine.
there are countless H6's with hundreds of thousands of miles on conventional oil, there's not some magic thing that happens to some engines and not others or some owners and not others. "i run 300k on all my vehicles with _________________" (insert favorite boutique brand, cheapest/on sale oil, or anything in between) is common and routine - all because it doesn't matter. choice makes insignificant differences for average daily drivers.
the many thousands of Subaru's making hundreds of thousands of miles over the decades make easy quantitative practical data. many of these run conventional without issues and synthetic without issues. and then if you dial in on the ones that do have issues, which *SHOCKER ALERT* does include synthetic oil users - you'll quickly learn the causes of oil induced failures and it's never oil choices. plenty of synthetic engines are blowing up too, but it's not the oil. it's poor maintenance.
* Usually it's just owners neglecting oil changes and leaks. i can't exaggerate how common it is. i can literally buy a blown subaru engine weekly that was run low on oil. who cares what oil you use if you're going to do that?
happens.
all.
the.
time.
