Oil for 2015 Subaru Forester XT (2.0 DI Turbo)

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It's been a long while since I've posted here; previously I had a SAAB 9-5 AERO (I liked ACEA A3 oils like Mobil 1 0W-40 and GC for that car) and then an Acura TL (Motorcraft semi-syn worked nicely there) and then an Acura MDX (Mobil 1 EP with Honda "FILTECH" filters work nicely for 15,000 miles) and then a couple of VW TDIs (I used to have a very a long commute), and stuck with VW's recommendation (VW 507.00) for those.

Back in the day, Auto-Rx was very popular here, and Pennzoil Ultra hadn't been created yet :)

Now I'm driving a 2015 Subaru Forester XT, and for those unfamiliar with the engine, it has the 2.0-liter four cylinder from the BRZ/FR-S, but Subaru changed the fuel injection from port+direct, to direct only, and turbocharged it.

It seems that direct injection engines have had problems with excessive carbon buildup on the intake valves (not all makes are equally affected, but in scanning various forums, BMWs, Minis, and Audis appear to be problematic)

As I understand, it's theorized that without port injection, there's no gasoline to wash off the buildup of recirculated crankcase vapors and oil on the intake valves and stems.

This Subaru "DIT" engine is relatively new in the U.S., so I've no idea if carbon build-up will be a problem, but I'd certainly like to choose an oil which might help minimize this problem. Of interest, is that Subaru recently shortened the oil change interval for this particular car to 6,000 miles (it was 7,500 miles last year)

Could Pennzoil Ultra help, with its increased cleaning power?
Could Redline help, also thought to be a very clean oil?
Do I look for an oil with low NOACK volatility like Amsoil?
Low SAPS? Low amount of VI? Just stick with Mobil 1?

So many factors!

I should also answer these questions:

1. What kind of vehicle you have : 2015 SUBARU FORESTER XT
2. What your owner's manual says -- not just viscosity, but certifications (look for acronyms like API SM, ILSAC GF-4, etc.) and change intervals as well : SYNTHETIC 5W-30, changed every 6,000 miles or 6 mos
3. Where you live : Northern Fairfield County, CT
4. How you drive (easy? hard? fast? slow?) : Sometimes slow, sometimes hard/fast
5. What your daily drive is like (short trips? long trips? city? highway?) : Country back roads, ranging from 25 mph to 55 mph, 13 miles each way to work and back
6. Whether your car has any known problems : None

Thanks for your thoughts.
Jason
 
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Your description describes my route and driving style nearly exactly.

Interested in reading what others have to say. Personally, I'm using up my stash of Rotella T6 and then GC. I have no idea what I'll run after that, but I?e got a couple of years to figure it out!
 
Stick with the spec 5W-30 grade. I would give consideration to a syn that meets the Honda HTO-06 turbo deposit spec' or an oil with a very low TEOST deposit score such as Castrol Edge.
 
On page 12-6 of your owner's manual it also requires the following in addition to 5w-30:

API classification SM or SN with the words “ENERGY CONSERVING” or “RESOURCE CONSERVING”.

-or-

ILSAC GF-4 or GF-5, which can be identified with the ILSAC certification mark (Starburst mark).

There are some good UOAs around here for the old Pennzoil Ultra 5w-30. I'd be willing to give the new one a try for 5,000 miles, and maybe get a UOA after the third OCI once the break-in period is over. Also, Rotella T6 is the standard for the turbo Subaru crowd. That comes with a bit of warranty risk if you don't have receipts for 5w-30 in some flavor.
 
CATERHAM you beat me to it! HTO-06 and a low TEOST are the key to having a healthy Di engine. I also recommend shortened OCIs since I read this on GF-6.com:

Compared to PFI engines, GDI and GDI-T engines have several unique features:

Increased production of fine carbon particulates during combustion, which can enter the crankcase via blow-by and cause excessive wear
Increased fuel dilution of crankcase lube oil (cylinder wall wetting by side-mounted direct fuel injectors allows fuel to contaminate the lube oil)
Increased oxidation and deposits due to higher operating temperatures and pressures
Higher initial cost than PFI engines for the higher-pressure fuel injection system
The one component that suffers the most from accelerated wear in GDI and GDI-T engines is the metal timing chain, which drives the camshaft(s) off of the crankshaft. Excessive wear can cause the check engine light to illuminate and could result in very expensive internal engine hardware repairs. Excess wear is evident in chain elongation, which can disturb valve timing and lead to degraded performance and higher engine-out emissions. Researchers are not yet sure about the exact wear mechanism—it could be abrasive wear from carbon particles suspended in the lube oil or an interaction between carbon particles and the lubricant, or both. A typical timing chain connecting the crankshaft and the overhead cams is shown below.

Hopefully this link will work:http://gf-6.com/node/75

As a result of all this I am running Castrol Edge in both my Ecobboost F150 and Mazdaspeed 3 and limiting the OCIs to 4k as I believe changing oil more frequently is cheaper than replacing timing chains. Will it work? How the heck do I know? But IF it works I'll be a happy camper.

Now let the long OCI fans jump in....
 
Keep in mind that Subaru lowered the OCI because sine of the newer engines are burning oil. It doesn't seem affect the turbos as much, but it's still worth keeping an eye on your oil level between oil changes, just to be sure.
 
Go thick until more data on engine is collected.

Redline Amsoil or Castrol 0w30
Mobil1 ESP 5w30
Pennzoil Euro Platinum/Ultra 5w30
Mobil1 5w30HM
Redline 5w30
Castrol FST

Or, spike the visc of any sn/gf5/dexos/hto06 5w30 with a quart of any of the 0w40 or 5w40's.
 
Thanks for all your valuable comments!

How ironic that this "new technology" (gasoline direct injection) causes more stress on the engine oil. Anyone know if BMW and MB have shortened their oil change intervals with the introduction of direct injection?

Will probably try Pennzoil Ultra Platinum...
 
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There are several uoa's on this engine over at subaruforester.org. This first five or six uoa's showed high fuel dilution (one at 6% is posted here in the uoa forum). The later uoa's showed better fuel dilution but all are still shearing GF5 5W-30's (including PU 5W-30) down to a 20 grade.

I'd stick with the severe service OCI of 3k unless you use a non Resource Conserving oil.

-Dennis
 
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