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2007 Forester Manual.
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118 Posts
Discussion Starter · #1 ·
So..... Our 07 does the expected "I'm going to use a quart of oil every 800 miles"... Or somewhere thereabouts.

We're running 5w30 full synthetic. (Walmart brand "SuperTech" WEeeeeeeeeeeeeee.... Hey, it meets the guidelines on the api label)

I'm trying to consider other ways to try and extended or reduce this oil consumption. Now 100% in the winter months here in NYS I'd run either 5w30 or 5w40 (used to run that 5w40 in our Bronco II. Engine loved it.) Probably only the 5w30 as the VVT operation uses tiny ports.

For the summer months where the external temp is above 40? I'm considering 10w30 or 10w40 (Synthetic). The ol' girl has over 218,000 on the engine and other then the oil consumption runs fantastic!

Any feedback on bumping it up to even 10w30 to try and reduce the usage? Rebuilding the engine isn't going to happen and I'm just trying to nurse 'er along. I'll be picking up a Subaru filter (or maybe napa gold....) in a few days to change out the oil for the summer/fall months.

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1998 forester
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111 Posts
@Tedybear315 I use 10w30 blends on both my Subarus. But then I live in Socal, so oil weight might be different for you. Have you had your car checked for any oil leaks like valve cover gaskets and such?
 

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2007 Forester Sports XT 4EAT
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2007 Forester Manual.
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118 Posts
Discussion Starter · #4 ·
No oil leaks on the ol' girl. We did the head gaskets about 13k ago (replaced 1 cracked head as well) and everything is buttoned up pretty tight. I'm actually impressed at how well it runs considering the miles it has. The oil consumption has been a constant sense day 1 of our ownership.

We're running the 'SuperTech' high mileage synthetic oil. 5w30 year round. With the warmer weather I'm going to do the oil change this weekend and will probably bump it to 10w30 for the summer months. Everything seems to point towards the engine burning the oil, but I'll be dipped if I can see even the slightest hint of any blue smoke upon startup or driving it.

I'd do 10w40, but that might be a little too thick for my liking. Might do the 5w40 for the winter/colder months. But we'll see.

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2004 FXT / 2020 Outback Onyx XT
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Age Old Oil Question

I would go with a different brand High Mileage oil. I can’t find much data on ST HM, but an old PQIA test showed the metallic additives to be a little low (although within spec). NOACK volatility came in slightly above spec at 15.2.

http://www.pqiamerica.com/June 2014/supertechHM.htm

Castrol Edge High Mileage is thicker at 100C (11.3 cSt’s) and has an extremely impressive NOACK volatility of 10% which is on par with some Euro specs (MB).

Mobil 1 High Mileage is even thicker at 100C (12.1) but they do not list their volatility.

https://mobiloil.com/en/motor-oils/mobil-1/mobil-1-high-mileage

Pennzoil conventional High Mileage xW-30 is 11.7/11.8 cSt’s. Pennzoil stopped listing their NOACK soon after they switched to GTL base stocks in their synthetics. Volatility was so low on the conventional oils that many people at bobistheoilguy thought that they possibly used synthetic base stocks in their conventional oils. And don’t get hung up on conventional vs blend vs synthetic as it doesn’t matter.

I’m a huge fan of 40 grades in turbo Subaru’s, but n/a cars typically do not need them. A 10W30 should be more stable as well and your manual allows them down to -4°F.
 

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2007 Forester Manual.
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118 Posts
Discussion Starter · #6 ·
Interesting as Supertech did manage to get high user marks. However Wallyworld carries other brands as well. (prices are decent as well). The wifes car gets Mobil-1 0w40 (VW Beetle) and I wish it was cheaper!. We'll look around on Friday when I get the supplies to get the maintenance done.

Oddly enough (or Fun Fact as my one employee loves to say). With a fresh oil change the consumption is a lot higher for several weeks. Then it slowly reduces as the oil gets more 'broken in'. (aka, loaded with engine residue from normal driving) Just the weirdest thing to note.

Looks promising for SuperTech's synthetic:

Petroleum Quality Institute of America - Data Template

Didn't see a high mileage report, but haven't much time as I need to haul freight into work this morning. We'll see what Wallyworld has on special. (And NO I'll never put a fram oil filter on it....)

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2004 FXT / 2020 Outback Onyx XT
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Age Old Oil Question

Yes, looks much better than the ST HM voa that I posted and I expect that the formula has been updated since then.

IMO, there’s no such thing as expensive oil at Wally World. Try picking up Mobil 1 0W-40 in Australia. If you get a 5L jug at a good deal it will cost ~AU$ 80. Just checked repco.com.au and it’s AU$ 103!
 

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2010 Forester Premium X AT
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What would really be interesting is to know how long you've been using that synthetic 5w30 and at what intervals. I've been using conventional 5w30 for about 205,000 mi with 6000 mi change intervals and am in the same neighborhood of oil consumption for my 2010.

Ie, does it make sense to pay extra use to synthetic for the life of the car?

As for the oil consumption, make sure the PCV valve has been changed. I think a lot of people get oil driven down the valve stem seals due to overpressure of the crank/valvetrain cases.

Other than that, I am starting to consider running 10w40. It is approved in my manual and it may save on the ~3 quarts I'm adding between every 6000 interval.
 
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