thinking about using extended drain oci in Subaru

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699
Location
USA
As l do not keep a stash of motor oil, l have been thinking what oil is next for my '15 Impreza. It will have about 86k miles on it at next oil change.

I started using Kendall GT-1 for about 9 oil changes, but transitioned to Supertech and Costco for the last 3 changes as these oils are readily available.

My current routine is to change air filter and CAF every other oil change. I was thinking about putting an extended drain oil in so l could change it once a year along with the AF and CAF to make life easier.

What are the pros and cons of running Mobil 1 EP (or similar) for about 12k miles instead of changing my generic oil every 6 to 7 k miles? Is it likely that l won't have to add oil for this longer interval as is the case with my 6 to 7k interval? Many Subaru vehicles seem to have oil consumption issues, but mine hasn't yet.

If l do go the extended drain route, should l use HM oil or standard M1 EP? Or should I keep changing it every 6k with generic oil as l do now?
Thought l would throw it out there for input and comment. l will go with what the prevailing opinion is here. If l had a huge stash of oil to work through, l wouldn't have this "problem".
 
Messages
59
Location
Northern California
My thoughts on this:
I do like your idea of streamlining maintenance. It is always good to have a little bit less on your mind to deal with.
However being said, For your mileage, using a HM Motor oil is the right path.
For the time being, I do not have a verdict on an extended OCI. Can you provide more specifics on what type of driving that Impreza sees?
 
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25,447
Location
Upstate NY
What year Subaru? Both my 2015 and 2016 Subaru vehicles required synthetic 0W20. So if a recent Subaru you should already be using synthetic.
 
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7,240
Location
North America
No need for HM oil unless you have leaks; but it won't hurt either.

If you're going to extend, do it via UOA rather than anyone's opinion.

Your filter changes seem pretty early...curious what their condition is when pulled at only12k miles.
 
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2,822
What engine do you have? I wouldn't do it with the 2.5 but that is me. I am doing 10k with Mobil 1 5-30 in my 17 Outback 3.6. My UOA is posted here and I could do 12k but that is above my comfort level.

2.5 in 2015 IIRC the burning issues was mostly fixed by then. What are you burning over say 5k now?
 
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97
Location
Mountains
I think Mobil EP would make it just fine depending on driving habits. Would I do it? No, but that's just me. At least swap filters every 5k if you are doing 10k+ oil changes.
 

wdn

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1,454
Location
NH
The 2015 Impreza has the FB20 engine, 2.0 liter port injected. It is the same engine, basically same car as the 2015 Crosstrek. The guy on the Crosstrek forum with the 2015 Crosstrek hr has driven almost one million miles, has been changing his oil every 12,000 miles with Mobil 1 EP 5W-20.
 
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295
Location
Houston, TX
The air filter changes seem excessive unless you are driving in very dusty environment. If that’s the case, then I wouldn’t extend the OCI that long.
 
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2,822
I'm sure it can, but should it?

The correct answer is it is engineered for 20k miles of filtration (I'm sure that is for a engine of good mechanical order). So frankly, it shouldn't be doing 2 12k OCI's. My error; I was thinking of my 10k OCI not the questioned 12k OCI.

It took me a while to get comfortable with a 10K OCI. I think the Subaru 3.6 and the conditions I drive were the perfect storm for me to go 10k and it worked out. I wouldn't personally do 24k of the Fram Ultra. I'd change it out with the 12k OCI.
 
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97
Location
Mountains
The correct answer is it is engineered for 20k miles of filtration (I'm sure that is for a engine of good mechanical order). So frankly, it shouldn't be doing 2 12k OCI's. My error; I was thinking of my 10k OCI not the questioned 12k OCI.

It took me a while to get comfortable with a 10K OCI. I think the Subaru 3.6 and the conditions I drive were the perfect storm for me to go 10k and it worked out. I wouldn't personally do 24k of the Fram Ultra. I'd change it out with the 12k OCI.

The 3.6 is a dang good motor, shame they got rid of it. But I love the FA24DIT so far, but I'd never run this engine over 5k the way I drive it and the places it goes. Now on my wife's Crosstrek, we do 8k intervals and her UOA's always came back solid using a variety of oils and a Napa Gold or factory filter. The engine in that Crosstrek is a total turd for power, but the fuel mileage and durability has been spot on.
 
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386
Location
MD
Thicker oil, as Vladiator suggested. Timing chains are not easy on oil in these engines. I would not exceed 5k miles in these engines, unless you don't care much and will swap cars before any damage (or performance degradation) is perceived. That's my 2 cents. I could very well be wrong but that's how I do things for my cars.
 

gathermewool

Site Donor
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8,590
Location
New England
I'm sure it can, but should it?

Yes.

OP, I plan on doing with my Legacy exactly what you're planning on doing, OCI-wise, as soon as my extended warranty is up. How? UOA-backed interval increase.

I agree with others that you're replacing your filters too often unless you live in an unusually dust/dirty area. Do you?
 
Messages
134
Location
NJ
I have 2 Subarus. A 18 Legacy with the 2.5 and a 19 Impreza. Because I am under warranty I do changes every 6 months or 6k miles which is what the manual calls for. I also change the CAF every year. Neither car is at the time limit for engine air filter yet. December will be 2.5 years since I got the Legacy. Right now it has 14k miles. If I wasn't having my wife drive the car it would be closer to 10 maybe 11k. January will be 1.5 years since I got the Impreza. I had planned on driving it a lot more but due to working from home and all my gigs pretty much being cancelled my estimated 6k+/yr mileage is now more like 1k. I have just over 6k on it now. I have being using M1 AFE in the Legacy. My Impreza had the first to OCs done at the dealer but will be going with M1 EP that I picked up on sale. If it weren't for the warranty I would probably be pushing a 12 month OC since I am barely driving but both cars are covered for 10yr/100k.

I don't see a problem with your plan but.... my opinion is you should do a UOA to see if the oil is holding up that long. If it does, continue. If it doesn't, adjust accordingly.
 
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82
The correct answer is it is engineered for 20k miles of filtration (I'm sure that is for a engine of good mechanical order). So frankly, it shouldn't be doing 2 12k OCI's. My error; I was thinking of my 10k OCI not the questioned 12k OCI.

It took me a while to get comfortable with a 10K OCI. I think the Subaru 3.6 and the conditions I drive were the perfect storm for me to go 10k and it worked out. I wouldn't personally do 24k of the Fram Ultra. I'd change it out with the 12k OCI.
I wouldnt run a fram for 500 miles....lol
 
Messages
2,493
Location
NJ
If you’re sticking with 0W-20, go with M1 EP HM for the boosted anti-wear levels. Only extend your OCI beyond Subaru’s recommendation very gradually and only based on uoa’s with TBN.

Personally I wouldn’t do it because UOA’s don’t catch everything (been there, done that), but you might be fine given that you’re n/a.

@Al has done some extended OCI’s in his Forester with good UOA results, but I don’t recall the model year.
 

Joe1

Thread starter
Messages
699
Location
USA
My thoughts on this:
Can you provide more specifics on what type of driving that Impreza sees?

Urban during the week. Highway on weekends.

I agree with others that you're replacing your filters too often unless you live in an unusually dust/dirty area. Do you?

CAF filter usually has lots of junk in it, but Air filter could probably go further.

I don't see a problem with your plan but.... my opinion is you should do a UOA to see if the oil is holding up that long. If it does, continue. If it doesn't, adjust accordingly.

I'm not planning on doing a UOA.
 
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