M1 5w30 / 2006 Legacy GT / 7165mi

[Schwinn]

7 months on the oil, I drive it relatively hard (not afraid of the redline), about 30 miles a day (each way) to and from work, plus whatever else. Of the 30 miles/day, about half is on the highway at high-speed (beyond posted limits, as everyone else), the rest is cruising at about 40mph (not a stop/go situation).

Air filter is Fram (I think)
Oil filter was M1
Northeast MA region

Air filter was changed probably about 15k miles ago, so it may be time to change it (certainly recommended by the result)...

I have my thoughts (misconceptions!), but would appreciate other's comments...

EDIT: The current oil-cycle is going to be on M1 again, but with the Subaru filter... see if that changes anything. I also plan on replacing the air filter, as recommended.

 

[addyguy]

Silicon is really, really high. At 40k miles, engine should be past break in, so look for an intake/air filter leak that is letting abrasive dirt into the system. That's where your bearing wear is coming from.

 

[buster]

Well, silicon is definitely the problem. Reduce that, and the rest will follow.

 

[Schwinn]

I plan to change the air filter tonight... didn't think it was that bad!

The data in text-form, to prevent losing the image later on:
MI/HR on Oil 7,165
MI/HR on Unit 40,436
Sample Date 10/11/2008
Make Up Oil Added 0 qts
ALUMINUM 5
CHROMIUM 1
IRON 16
COPPER 17
LEAD 15
TIN 1
MOLYBDENUM 85
NICKEL 0
MANGANESE 1
SILVER 0
TITANIUM 0
POTASSIUM 1
BORON 38
SILICON 45
SODIUM 12
CALCIUM 2198
MAGNESIUM 14
PHOSPHORUS 602
ZINC 764
BARIUM 0
SUS Viscosity @ 210°F 56.4
cSt Viscosity @ 100°C 9.18
Flashpoint in °F 380
Fuel % Antifreeze % 0
Water % 0
Insolubles % 0.4
TBN 2.8

 

[JoeFromPA]

I posted over at LGT.com, but if your air filter is the problem it's because of a poor seating or [censored] filter....it shouldn't be filtering poorly after only 15k miles.

At 40k/4 year old turbo vehicle, you could have a vacuum leak/leak somewhere else in the intake system. Would be unusual, but not rare.

I'm not a huge fan of this, but because the Legacy GT has the worst air filter replacement procedure I've ever seen....it might not be a bad idea to insert a new filter with a line of some sort of sealant around the edges to ensure it seats/seals properly.

Joe

 

[Solo2driver]

Another turbo Subaru run too long, on Mobil 1 5w30. Not placing all the blame on the air filter here, we have seen way too many UOA's and replaced engines from your combo, even in street applications.

My recommendation (if worth anything) is if you must use M1, use another flavor (like 0w-40), and change it at 5K if you must go "long drain". Subaru went to 3,750 mile OCI's for a reason, and not just from turbo line screen/dino oil/etc.

 

[JoeFromPA]

Solo2driver - I think it's impossible to blame M1 here; the Silicon masks the truth. It's viscosity held up just fine and it's flashpoint is reasonable (a tad on the low side). It has active additive left. What would make you think the oil was worn out or did not protect properly?

While I definitely agree with you that M1 5w30 has a history of poor UOAs in this car, and I actually recommended to the OP to switch to M1 0w40 if he wants the same cost/brand (I did this on LGT.com), I think it's over the top to say 5,000 mile OCIs with a higher quality oil should be the extent.

Subaru went to 3,750 mile OCIs because some, even quality, oil couldn't sustain the 7500 mile runs in this turbo application. But I can show you UOAs with AMSOIL after 10-15k runs in this application where the engine is doing swell.

Joe

 

[buster]

Do these engines prefer 40wt oils? M1 TDT?

 

[JoeFromPA]

Buster - These engines shear most 30wt oils pretty quickly (dino at least). IMO, they prefer 40wts when being driven in the nature the OP is describing, especially if even modestly tuned....and it's very easy to tune this car.

Joe

 

[buster]

Thanks Joe.

 

[Schwinn]

Oh yeah, the motor is "modestly tuned" - Stage 2 (higher boost, and some exhaust pipe changes).

So, if not M1, what oil would people recommend? I have used M1 for many years on my previous cars, and loved it. I'd like to stick to a quality synthetic, but want one that's easily available too (not Amsoil, as I question their claims and it's a pain to obtain it at a reasonable price).

 

[buster]

I would use Mobil 1 5w-40. Won't find a better, more readily available oil IMO.

 

[bluesubie]

I agree with Solo2 and, FWIW, even Blackstone recently commented that they see a lot of high copper in turbo Subaru's running M1 5w30. That was in a 2.0 UOA from nasioc that I recently posted here.

IMO, mod your car and mod your oil.

According to the manual, 10w30 and 10w-40 can be used in temps of over 0F so I think buster's M1 5w-40 is a good recommendation.

What air filter are you going with?

-Dennis

 

[SubLGT]

Originally Posted By: Solo2driver
Another turbo Subaru run too long, on Mobil 1 5w30. .....


I would say the main culprit here is dirt ingestion, and not the M1. A leak in the intake system somewhere, or a poorly sealed air filter.

 

[edhackett]

Yes, the Subaru turbo engines seem to do better on an oil that is around 12-14 cSt, and meet A3 specs.

GC - Castrol Syntec 0w30 works well for up to 7.5K
Mobil 1 0W-40, 5W-40 TDT, and HM 10W-40 would all be worth a try.

I run Rotella T 10w30 at 3.75K intervals in my 2008 Legacy GT with good results.

Ed

 

[JoeFromPA]

Ed,

Didn't know you had an LGT

I'm going to get Mobil One 0w40 Euro Formula under the deal of "5 quarts of any mobil one w/ a pureone filter for $30".

Running Pennzoil Platinum since 3000 miles on my-now 11000 mile 08 LGT 5-speed....seems quite happy with the oil. But I'm using it cause it's cheap, quality synthetic for these 3.75 mile changes. Once warranty is up, 7500 miles here I come!!!

Joe

 

[buster]

Originally Posted By: SubLGT
Originally Posted By: Solo2driver
Another turbo Subaru run too long, on Mobil 1 5w30. .....


I would say the main culprit here is dirt ingestion, and not the M1. A leak in the intake system somewhere, or a poorly sealed air filter.


Yeah, that Si is way too high.

 

[bulwnkl]

Isn't it odd that Si is too high (obviously), and yet there isn't very much wear coming off the aluminum pistons?

There's a fuel problem here, too, whose effects are a significant factor in Subaru's change to short drain intervals.

 

[Schwinn]

bulwnkl: As I recall, most Al blocks have sleeves on them, which is where the pistons actually ride... this is why you won't see Al in a wear situation (as you can imagine, Al doesn't wear very well). Alternatively, manufacturers of Al blocks often coat the piston walls with something to prevent the fast wear common to Al, which again prevents direct Al-piston wear...

Fuel problem? What fuel problem are you seeing?

EDIT: Incidentally, didn't get to buy an air filter last night - Autozone only carries STP and Fram, and the next nearest auto parts store is either far away or closed by the time I get out of work. Man I'm starting to hate Autozone.

I was either going to get a Purolator or the OEM filter (OEM parts desk is nearby)... anyone have other recommendations/sources?

 

[jennings]

You might try Rotella Syn 5w40. I'm on my second change with it and, while I have no UOA, it does seem to stay in the car better. Consumption has gone way down compared to 5w30 syns. Easily less than a qt. per 5K, which is the interval I'm doing.