2020 Subaru Legacy 2.5L; M1 EP 0w20 21k mile OCI

Last time I saw 30ppm of iron in a uoa I was breaking in a new small air cooled engine that didn't have an oil filter.
Last time I saw over 60ppm of silicon on an oil test was on an engine where the air filter came loose and I'm in a very dusty environment.
 
Last time I saw 30ppm of iron in a uoa I was breaking in a new small air cooled engine that didn't have an oil filter.
Last time I saw over 60ppm of silicon on an oil test was on an engine where the air filter came loose and I'm in a very dusty environment.

I'm still missing the part where this is a problem. Again, the wear rate is as would be expected. (better than expected) Are you concerned that the wear metals in the oil will contribute to more wear? That hasn't shown up so far. It takes 100+ ppm for that to occur which is why the agreed upon condemnation limit on wear metals is 100 ppm. There's nothing wrong here. You're arguing a problem that doesn't exist.
 
Is this Subaru engine DI?

Apparently you only get an answer if you ask twice.

The long daily round trip commute has got to be key to this very nice UOA.

Unlike other UOAs of the same oil that did not look nearly as good with half the mileage.

The silicon is a concern, however, absent the OP finding an issue in and around the air intake and filter box, his driving on dusty gravel roads has to be somewhat contributing to that elevated number.
 
When I get to around 15,000 miles on the oil, the car is nearing the bottom mark on the dipstick, so I add a quart which takes it to the top mark (full).
So about 10oz per 5k miles. Not bad. Have you replaced the PCV recently? It’s understandable with all the highway miles; my EJs never used any oil until I was driving them for at least an hour and a half at 2700+ RPM, which is about 72-75mph with the short-legged 4EATs and 4.111 differentials…
 
No, I haven't replaced the PCV. I was going to at 200,000 miles.

I don't feel oil usage is linear. Not just in this car but in others as well, I notice more usage later in the run. This could just be what I "see" or notice, and it may actually be more linear.
 
Apparently you only get an answer if you ask twice.

The long daily round trip commute has got to be key to this very nice UOA.

Unlike other UOAs of the same oil that did not look nearly as good with half the mileage.

The silicon is a concern, however, absent the OP finding an issue in and around the air intake and filter box, his driving on dusty gravel roads has to be somewhat contributing to that elevated number.
I think the OP results are excellent. However I just can’t make any sense of it. It’s been repeatedly said here and in other Subaru forums that there’s no difference in dilution with highway or city with FB25DI. Almost everybody has fallen out of grade rapidly by the 2-3k mark on 0w-20. Even I did a Amsoil Signature 0w-20 run and around 4800 miles viscosity was around 7.6. How is that M1 EP is doing 15k-20k miles and not thinned out. Something ain’t right here. Either the engine isn’t DI or the OP just happens to have a real tight engine as far as tolerance stacking goes with his rings/ cylinder. The results are about 99% contradictory to almost all Subaru DI results by a large margin even with 30 weight oils.
 
I think the OP results are excellent. However I just can’t make any sense of it. It’s been repeatedly said here and in other Subaru forums that there’s no difference in dilution with highway or city with FB25DI. Almost everybody has fallen out of grade rapidly by the 2-3k mark on 0w-20. Even I did a Amsoil Signature 0w-20 run and around 4800 miles viscosity was around 7.6. How is that M1 EP is doing 15k-20k miles and not thinned out. Something ain’t right here. Either the engine isn’t DI or the OP just happens to have a real tight engine as far as tolerance stacking goes with his rings/ cylinder. The results are about 99% contradictory to almost all Subaru DI results by a large margin even with 30 weight oils.
Is it possible that it’s oxidative thickening? Im not sure. My non DI 2018 Outback always shears a grade. My opinion is the timing chains are hard on oil. The new DI certainly didn’t help with dilution on top of that.
 
When I get to around 15,000 miles on the oil, the car is nearing the bottom mark on the dipstick, so I add a quart which takes it to the top mark (full).
That’s really good! My 2018 Outback uses oil to the tune of a quart every 2500 miles. Didn’t burn much at all until after 60k. The new engines seem to have cured the problem.
 
I think the OP results are excellent. However I just can’t make any sense of it. It’s been repeatedly said here and in other Subaru forums that there’s no difference in dilution with highway or city with FB25DI. Almost everybody has fallen out of grade rapidly by the 2-3k mark on 0w-20. Even I did a Amsoil Signature 0w-20 run and around 4800 miles viscosity was around 7.6. How is that M1 EP is doing 15k-20k miles and not thinned out. Something ain’t right here. Either the engine isn’t DI or the OP just happens to have a real tight engine as far as tolerance stacking goes with his rings/ cylinder. The results are about 99% contradictory to almost all Subaru DI results by a large margin even with 30 weight oils.
Depends on all on operation conditions. Our DI car can hit 5% fuel by 4,000mi doing short trips in the winter. But then if we have a busy summer doing road trips every few weeks it will test 0.5% fuel at 7,000mi.
 
Is it possible that it’s oxidative thickening? Im not sure. My non DI 2018 Outback always shears a grade. My opinion is the timing chains are hard on oil. The new DI certainly didn’t help with dilution on top of that.
Amsoil did tons of testing tests where they showed viscosity changes of "the competitions oils" probably one of those was mobil1 (they didn't tell you the brand). Amsoil was able to show viscosity breakdown typically happening from 0 to around 5,000 miles where it leveled off. Then somewhere around 5k to 6k oil began gradually oxidative thickening through 20,000 miles. Then after 20,000miles oxidative thinking took off and by 25,000mi you could be looking at potential having a viscosity of dozens of cSt at 100c. It was on an amsoil or maybe even a banks+amsoil video I watched a while ago, all about extended oci.
 
Is it possible that it’s oxidative thickening? Im not sure. My non DI 2018 Outback always shears a grade. My opinion is the timing chains are hard on oil. The new DI certainly didn’t help with dilution on top of that.
Amsoil did tons of testing tests where they showed viscosity changes of "the competitions oils" probably one of those was mobil1 (they didn't tell you the brand). Amsoil was able to show viscosity breakdown typically happening from 0 to around 5,000 miles where it leveled off. Then somewhere around 5k to 6k oil began gradually oxidative thickening through 20,000 miles. Then after 20,000miles oxidative thinking took off and by 25,000mi you could be looking at potential having a viscosity of dozens of cSt at 100c. It was on an amsoil or maybe even a banks+amsoil video I watched a while ago, all about extended oci.
I talked with David Ward about my No VII Euro thickening from 11.2 to 12.7cSt over almost 15k miles without much change in oxidation value.

Part of the thickening occurs as the lighter ends of the oil evaporate and make its way thru the PCV system, like what has been shown in my catch can & analyzed also. This leaves the heavier stuff behind, and will naturally show as thickening but it’s really just the absence of the thinner viscosity parts that have “boiled off”, if you will.

The other mechanism at work here is the “work hardening” aspect that all oils experience over time in service. The longer an oil is in use, the thicker it becomes. This is separate from oxidative thickening.

The long OCI combined with minimal oxidation increase and the OP’s point that the car uses about a quart every 15k leads me to believe we’re seeing both these phenomena. Then toss in a full quart of makeup oil that is right back at the baseline viscosity, and voíla. Perfect viscosity on a really long OCI.
 
Alright, keep up with your 20k intervals and when you reach 300k lets see how healthy and clean that engine actually is.
You must have missed @wwillson’s borescope pics inside his engine after a 34k OCI, even with elevated oxidation. Horrible, I tell you! If everyone followed his lead, he would run machine shop parts washers right out of business!! 😮
 
You must have missed @wwillson’s borescope pics inside his engine after a 34k OCI, even with elevated oxidation. Horrible, I tell you! If everyone followed his lead, he would run machine shop parts washers right out of business!! 😮
Yea because a single run out to 34k is equal to many runs out to 300k.
 
I don't feel oil usage is linear. Not just in this car but in others as well, I notice more usage later in the run. This could just be what I "see" or notice, and it may actually be more linear.
That seems to be common. I think as the oil loads up with contaminants is when it starts to happen.

You really need a oxidation/TAN value.

Mobil 1 is very oxidation resistant.
 
I think the OP results are excellent. However I just can’t make any sense of it.... The results are about 99% contradictory to almost all Subaru DI results by a large margin even with 30 weight oils.
Agreed.
 
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