Changing weights in a Subaru?

[jhskier25]

Hi all,
Long time fan of the site, but this is my first topic. I'm very excited to hear the opinions of those here smarter than I. I have a 2011 Forester with 40000 and the FB25 engine that specs synthetic 0w-20 but allows for conventional 5w-30 and 5w-40 only as a top-off (even though conventional 5w-40 doesn't exist...).
Here's the deal: I'm currently on a run of Amsoil Signature and am about to hit 11,000 on this OCI. It was almost entirely short tripped so the oil, in my opinion, is near shot. The thing is, I genuinely love changing the oil in my car (as many here can relate to) and would actually prefer to do changes around 4k -- just about the length of time it takes me to get obsessed with a new oil here on BITOG. I love the PQIA numbers on PYB 5w-20. Seeing as changing a synthetic at 4k Is likely a waste, would I be doing my engine harm by using the 5w? Should I use the conventional only in the summer? Is it really necessary to go for M1 AFE when a bottle of VWB 5w-20 would do the trick? Is motorcraft 5w-20 semi-syn worth a shot?
Thanks so much for the replies in advance! This community is an awesome source for automotive knowledge and I appreciate you guys taking the time to answer

 

[Clevy]

Your plan sounds reasonable. Your right about 4000 miles on syn being a waste. I suggest doing a used oil analysis on the 5w-20 just to insure your plan works.

 

[Merkava_4]

Let me get this straight:

You're worried about going from 0W-20 to 5W-20 ?

 

[FL_Rob]

If you're short tripping all the time conventional 5w20 is the ticket.These engines are not hard on oil.

Change is good.

 

[pbm]

You should have no problem running one of those fine 5w20's for even 5K (pyb or qsgb would be my top choices).
I might stick with the syn 0w20 in Maine winter though.

 

[LoneRanger]

No. The i-Active Valve Lift system on the FB engine is designed to use the characteristics of 0W20 to function to spec. The system uses the engine oil via a series of orifices to do it's thing. While 5W20 may not make a difference, anything heavier is not recommended for oil change fill. This was discussed a lot on subaruforester.org when the FB engine first came out. There also used to be a youtube vid by a Subaru master tech who explained it.

Why try to re-invent the wheel? Subaru powertrain engineers probably knew what they were doing when they designed the i-Active system and made the oil viscosity recommendation.

 

[ARCOgraphite]

I was thinking of going to a 5w30 DEXOS spec pennsoil on our FB25 that has 60K on it now and uses about 1 qt between OCI at 7000-7500 miles. Thes engines aren't as easy on the oil as the old EJ given the EJ SOHC was rollerised and had a dry timing system (belts) and no VCT - but it isn't as demanding as a hot turbo, that's for sure. I might just go to PU5w20. If the VCT and the HLA provide ample torque down low (1500-2000rpm) with the 5w30 I wouldn't worry about the viscosity - though I wouldnt put a 40 or a 50 in there. The VCT has to work with oil over 10,000 cSt when warming during the commute in the winter, so I think it can work with a 30 that's a mere 2 cst more viscous than a 20 when warm. The Subaru tech talking about the small orifaces in the VCT oiling system requiring a 20 grade is just pure bologna.

 

[ARCOgraphite]

I was thinking of going to the 5w30 DEXOS spec pennsoil on our 2011 FB25 that has 60K on it now and uses about 1 qt between OCI at 7000-7500 miles. Thes engines aren't as easy on the oil as the old EJ given the EJ SOHC was rollerised and had a dry timing system (belts) and no VCT - but it isn't as demanding as a hot turbo, that's for sure. But I might chicken out and just go to PU5w20. If the VCT and the HLA provide ample torque down low (1500-2000rpm) with the 5w30 I wouldn't obsess about the viscosity - though I wouldnt put a 40 or a 50 in there. The VCT has to work with oil over 10,000 cSt when warming during the commute in the winter, so I think it can work with a 30 that's a mere 2 cst more viscous than a 20 when warm. The Subaru tech talking about the small orifaces in the VCT oiling system requiring a 20 grade is just pure bologna.

 

[Clevy]

Originally Posted By: LoneRanger
No. The i-Active Valve Lift system on the FB engine is designed to use the characteristics of 0W20 to function to spec. The system uses the engine oil via a series of orifices to do it's thing. While 5W20 may not make a difference, anything heavier is not recommended for oil change fill. This was discussed a lot on subaruforester.org when the FB engine first came out. There also used to be a youtube vid by a Subaru master tech who explained it.

Why try to re-invent the wheel? Subaru powertrain engineers probably knew what they were doing when they designed the i-Active system and made the oil viscosity recommendation.



Yeah. Dodge said the same thing about mds and I've gone from a 20 grade to a 40 grade and there was a millisecond difference in engagement time.
So basically nil.
How much of a difference do you really think a 20 and 30 grade have at oil temps of 200f.
Op
I've got no experience with a Subaru however I do with an mds equipped hemi. The hemi uses oil pressure to close valves on 4 cylinders which is how the mds on these work. I expect yours to be similar.
I've gone 2 grades thicker without any harm nor any real world difference in how the engine behaves.
Use whatever grade you like. Get a used oil analysis done to make sure the oil can handle it.

 

[ColdCanuk]

Originally Posted By: FL_Rob
If you're short tripping all the time conventional 5w20 is the ticket.These engines are not hard on oil.

Change is good.


The FB25 has an oil consumption issue. How can you say this? Just google FB25 oil consumption. You can argue the number of people with consumption issues all you want but to say these engines (FB25) are not hard on oil is way off.

I use Amsoil SS 0W20 but have been thinking to trying SS 5W20 or the SS 0W30.....It's just I live in a cold climate so I have respect for the cold start up and a '0' at the beginning. The consumption issue with the new FB25 engine is discussed through thousands of posts on the Forester site, thousands seriously.

 

[BHopkins]

Originally Posted By: Merkava_4
Let me get this straight:

You're worried about going from 0W-20 to 5W-20 ?


You need to understand that the Owners Manual for Subaru's with the FB25 are very specific about the use of anything buy 0W-20 synthetic. The manual states that if needed, other oils may be used, but at earliest convenience, the oil should be changed back to 0W-20 synthetic. I don't know that this is in the manual for the '11 Forester, but I remember reading it in the manual for my '13 Outback. Just looked for it so I could be accurate in quoting it, but couldn't find it right now.

 

[NO2]

Why would you risk invalidating your Subaru warranty with an extended OCI? I'd wait until you are past your 5/60 warranty and stick with a 0w-20 given both the Subaru spec and the cold Maine winters. The FB25 engine specs a bypass pressure of around 23 PSI, and many 3rd party filters are far lower (11-12).

 

[fdcg27]

You apparently thought of this twice

 

[pbm]

The difference between 0w20 and 5w20 at anything other than artic temps is basically nothing.

 

[bluesubie]

Originally Posted By: ColdCanuk
Originally Posted By: FL_Rob
If you're short tripping all the time conventional 5w20 is the ticket.These engines are not hard on oil.

Change is good.


The FB25 has an oil consumption issue. How can you say this? Just google FB25 oil consumption. You can argue the number of people with consumption issues all you want but to say these engines (FB25) are not hard on oil is way off.

I use Amsoil SS 0W20 but have been thinking to trying SS 5W20 or the SS 0W30.....It's just I live in a cold climate so I have respect for the cold start up and a '0' at the beginning. The consumption issue with the new FB25 engine is discussed through thousands of posts on the Forester site, thousands seriously.

Bad oil control rings is a design issue, but I do not see how that makes the car hard on oil. UOA's are still good from what I recall.

-Dennis