2008 Subaru Legacy 2.5 N/A

[astraelraen]

We just picked up a 2008 Subaru Legacy with the 2.5 N/A engine. Currently it only has 1200 miles on it and I'm looking for the first oil change very soon here.

The EPA numbers are 20/27 mpg. My wife is actually getting roughly 24mpg with her 50/50 city/hwy trips, which is pleasantly more than I was expecting.

The car is driven moderately for the most part. It probably doesn't see much greater than 4000rpms in 80+% of its driving. The manufacturer suggests 5w30. But I was wondering if 5w20 might actually help bump that mpg number up into the 25+ range, which I would be overjoyed with.

It is driven roughly 7000-10000 miles per year. I would ideally do 2 oils changes per year. One after winter and one after summer.

Manufacturer warranty/recommendations aside, would a good synthetic 5w20 oil make it? I don't see very many Subaru UOA's and most of them are for the turbo motors that I do see.

 

[02zx9r]

a 5w20 dino or synthetic would do you good for 2 a year changes.

 

[drewjp]

Motorcraft 5W-20 would work just fine for 2x/year OCI, as long as no consumption issues arise.

M1 0W-20, or the new PP 0W-20 would last a full year with those driving conditions.

 

[bluesubie]

I think there's at least one n.a. 2.5L Subaru owner in the U.S. running xw20 and posts uoa's. oilyriser maybe?

edit: Found the uoa here.
IMO, your mpg's may also improve as you put additional miles on the car.

-Dennis

 

[astraelraen]

Thanks for the link.

I guess I doubt that a good 5w20 would have serious detrimental effects, especially during the winter. But our summer months will see >100F for a month straight usually. I don't know how well 5w20 would hold up under those conditions compared to a 5w30.

I suppose testing is the only real way to find out. I may wait until the winter when I feel it is "safer" to run a 5w20.

 

[bluesubie]

Another option is to look for an xW30 with a thin viscosity at 100C and a low High Temp. High Shear. Low HTHS should give you better gas mileage.

I found the best thing for improving mileage was doing the posted speed limit. That lasted for about two weeks before I decided that was unsafe to do on the New Jersey Turnpike.

-Denis

 

[Bill in Utah]

I have a 2007 Outback and live in the state below you.

Excellent UOAs with Halovine and PP. I'll have another UOA in a week or so.

Titan also has posted UOAs on his Subarus.

Follow the manual, run a 5w-30 oil (any SM) and change it every 6 months and you are protected as well as ANY oil.

Subarus are EASY on the oil but I would not run a 5w-20 BECAUSE of warranty concerns. I buy new cars and keep them for a long time and have never had any problems with engines. My 1986 Jetta has 327k miles on it and still has never needed any engine work. All on yesterdays conventional oils.

Todays conventional oils are a LOT better. Use with no worries.

I've been using PP only due to it being on sale for under a buck. And I've bought some other Syn for testing to see if there is a difference. So far, more $$.

The Subarus can take a hit and protect the passengers. Last Oct our new Outback was hit by a semi, no one was hurt and they fixed the car and its fine now.

Take care and enjoy the new ride.

Bill

 

[glennc]

I bet the mileage will improve a bit as the engine loosens up. I'd only expect a 2% gain at most from going down an oil grade, though it might be worth it if there's no downside. Warranty?

A lot of xW-30s seem to thin into 20wt range by the time they are changed. Never any apparent detrimental effects from it though.