Subaru 2.5L 40k; Mobil EP 0W-20 6.8k

[ford250]

UOA on Mobil EP 0W-20 6,800 miles on my sons Subaru. Silicon a little high.

 

[Deleted member 89374]

"Try 9K miles." - Uhm, nope...

It's safe to say that you should run M1 EP 5W-30 without any concern or issue as you're dealing with fuel dilution that may be out of your control. I would definitively cut back the OCI to 5K miles and stay there.

Looks like "Triple Action+" oils are well formulated, as the fuel did not affect the ZDDP ppm count. It did, however, cause some shearing that turned your 0W-20 into a 0W-16. Yes, technically it's still a 0W-20, but effectively no 0W-20 ships with a viscosity of 6.65 cSt @ 100C.

 

[FMC]

The 100C viscosity of this oil is 8.8, so it sheared to 6.6, That is cause for concern.

 

[JRHAWK9]

This is why I have changed my oil in my 2.5 FB25 in my '21 Crosstrek at 3 month intervals.

I'm now moving to 5w30 HPL PCMO and will be doing 4 month intervals (somewhere around 3,000 miles I'm guessing).

UOA on Mobil EP 0W-20 6,800 miles on my sons Subaru. Silicon a little high.

How was this car driven (highway, city)?? How much time was this oil in service for?

 

[Oliveoil2]

That’s a good uoa. Check the air filter and connections.

 

[ford250]

This is why I have changed my oil in my 2.5 FB25 in my '21 Crosstrek at 3 month intervals.

I'm now moving to 5w30 HPL PCMO and will be doing 4 month intervals (somewhere around 3,000 miles I'm guessing).



How was this car driven (highway, city)?? How much time was this oil in service for?

90% highway miles

 

[fantastic]

Even with the higher silicon & fuel there was not any heavy wear present in this sample. It doesn't look real bad IMO.

 

[CharBaby]

Good Report!
Indeed, do check the air filter.

 

[Deleted member 89374]

I think it sheared the VII, however, that shouldn't have any significant impact on the actual HTHS of the motor oil, otherwise we'd see a spike in wear numbers. Granted, Blackstone Labs only tests for wear at 5µ. Next time I'd use someone like SPEEDiagnostix, as they also test for 10µ particles.

 

[chris719]

Even with the higher silicon & fuel there was not any heavy wear present in this sample. It doesn't look real bad IMO.

UOA doesn’t tell you very much of anything regarding wear. I’ve seen pristine Blackstone histories for engines that would go on to spin rod bearings. An absence of evidence is not evidence of absence, as Sagan said.

 

[Bellavita]

The wear metal numbers are superb and the engine lives a good life with 90% highway miles. The Subaru OCI is 6,000 miles and you changed at 6,800 . . . excellent. And synthetic oil is being used so everything is being done per the Subaru textbook.

I agree with CharBaby and check the air filter box to to see if the air filter is properly installed. You may want to pull it and inspect the surrounding gasketing to determine if it is sealing completely. It may be best to go ahead and replace it if anything is suspect.

 

[Bellavita]

I failed to ask;
What oil filter are you using?
Did you experience any oil loss on the dipstick over the 6,800 miles?

 

[Jimmy_Russells]

Good report

 

[TiGeo]

The viscosity drop is just fuel. Any BS report showing any fuel is typically WAY more than it they estimate. Silicon - check your air filter/connections. I take it this is a standard paper filter?

 

[fantastic]

UOA doesn’t tell you very much of anything regarding wear. I’ve seen pristine Blackstone histories for engines that would go on to spin rod bearings. An absence of evidence is not evidence of absence, as Sagan said.

UOA's can pick up trends & there is a range of acceptable metals, from wear, contaminating the oil. UOA's are an excellent measurement that can show when there may be mechanical things needing attention. Symptoms of the engine can help pinpoint along with scan tools. It is a valuable piece to the puzzle IMO. Rod bearings can spin at any time unfortunately but that should absolutely increase wear metals in a UOA as a result. I'm a Sagan fan & all the others that followed in his footsteps Dawkins, Neil deGrasse Tyson, etc.

 

[chris719]

UOA's can pick up trends & there is a range of acceptable metals, from wear, contaminating the oil. UOA's are an excellent measurement that can show when there may be mechanical things needing attention. Symptoms of the engine can help pinpoint along with scan tools. It is a valuable piece to the puzzle IMO. Rod bearings can spin at any time unfortunately but that should absolutely increase wear metals in a UOA as a result. I'm a Sagan fan & all the others that followed in his footsteps Dawkins, Neil deGrasse Tyson, etc.

I think it's fair to say that if a UOA shows a problem then there is a problem, but it definitely does not rule out there being "excess" wear. I literally saw a thread a month or two ago on Bimmerpost where some guy took a sample of glittery oil from an oil filter housing and sent it to Blackstone and it came back within averages for that motor. The sample prep and method used by the lab are key... Rod Knock highlighted it perfectly.

If UOA showed wear to any consistent degree, then you wouldn't have as many expensive and laborious tests required for oil approvals. If you read some random SAE papers, you'll find various methods to estimate wear but none of them are UOA via ICP that I have come across in my limited sampling.

 

[kschachn]

UOA's can pick up trends & there is a range of acceptable metals, from wear, contaminating the oil. UOA's are an excellent measurement that can show when there may be mechanical things needing attention. Symptoms of the engine can help pinpoint along with scan tools. It is a valuable piece to the puzzle IMO. Rod bearings can spin at any time unfortunately but that should absolutely increase wear metals in a UOA as a result. I'm a Sagan fan & all the others that followed in his footsteps Dawkins, Neil deGrasse Tyson, etc.

There is no trend here.

 

[ford250]

I failed to ask;
What oil filter are you using?
Did you experience any oil loss on the dipstick over the 6,800 miles?

Fram Ultra

 

[ford250]

The viscosity drop is just fuel. Any BS report showing any fuel is typically WAY more than it they estimate. Silicon - check your air filter/connections. I take it this is a standard paper filter?

Factory replacement

 

[Bellavita]

Fram Ultra

Awesome.