2018 Subaru Forester 15,000 mile HPL OCI

[mt23]

2018 Subaru Forester 2.5i 6 speed manual. First time using HPL. I changed oil filter at 5k, and 10k. The 5k filter showed signs of cleaning, the 10k much less so. This past interval saw harder use than other intervals and was over winter months. Many short and moderate trips, usually enough to get oil temp above 210 for some time on the moderate trips. Car was driven 2 hours right before sampling oil hot.

Halfway through interval I noticed air filter box not perfectly clamped together and corrected it. The box was correctly slotted together but was not clamping flush and true.

I'm not concerned yet about fuel dilution. Yes I know blackstone is not accurate here. This engine is port fuel injection and I attribute the fuel presence to winter use but will monitor. Fuel trims are spot on and there are no other reasons to suspect a problem. The oil on dipstick and under the oil fill cap did smell like a direct injection engine oil starting part way through the winter.

1.75 quarts added. .75 quarts added from pcv valve issue during one long highway trip. 1 quart between both oil filters and normal consumption over interval.

 

[JustN89]

Excellent report, outside of the fuel dilution. I know you’ve said you’re not worried about it, and whether you should be or not, it’s definitely diluting and in significant amounts between the Fuel % and the lowered flashpoint. Wear metals look great though and the TBN is awesome for 15,000 miles!

 

[TiGeo]

Flashpoint at 360 and showing any fuel is quite a bit for a Blackstone UOA.

 

[mt23]

Given the presence of fuel I'm impressed the viscosity is 30 weight. We'll see what the next oil interval does with all warmer weather driving. So far I've driven 5500 miles on a cross country trip. I am a little surprised by the fuel, I do keep short trips to a minimum when possible, and once it's made a short trip I always take a longer one to get everything up to temp. It does see wot and redline regularly as well.

 

[fantastic]

That's great you went to inspect the poor seal on the air box & found the culprit. This is a very good report w/the fuel not doing any harm that we can tell from this UOA.

 

[Lubener]

I am surprised with such a high TBN after that many miles.

 

[TiGeo]

Given the presence of fuel I'm impressed the viscosity is 30 weight. We'll see what the next oil interval does with all warmer weather driving. So far I've driven 5500 miles on a cross country trip. I am a little surprised by the fuel, I do keep short trips to a minimum when possible, and once it's made a short trip I always take a longer one to get everything up to temp. It does see wot and redline regularly as well.

Because at that OCI you've likely had thickening from oxidation.

 

[fantastic]

Because at that OCI you've likely had thickening from oxidation.

I have more experience with OPE so take this with a grain of salt. All the oil changes that had fuel contamination & especially engines loaded with fuel from a bad carb came running out the drain hole like ol faithful. Viscosity of water.

Fuel is less viscous than oil obviously so my speculation is there is no oxidative thickening from the fuel itself yet. Visc still in range & a very strong TBN shows fuel not doing much harm here.

But to your point.. If the fuel was in for a long time & degraded from the oil no longer neutralizing the fuel then it could thicken a bit. Think of old fuel left in a lawnmower for some time. It can leave a sticky molasses substance. However, I don't think this has happened YET in this sample since this HPL oil has plenty of TBN left.

 

[TiGeo]

I have more experience with OPE so take this with a grain of salt. All the oil changes that had fuel contamination & especially engines loaded with fuel from a bad carb came running out the drain hole like ol faithful. Viscosity of water.

Fuel is less viscous than oil obviously so my speculation is there is no oxidative thickening from the fuel itself yet. Visc still in range & a very strong TBN shows fuel not doing much harm here.

But to your point.. If the fuel was in for a long time & degraded from the oil no longer neutralizing the fuel then it could thicken a bit. Think of old fuel left in a lawnmower for some time. It can leave a sticky molasses substance. However, I don't think this has happened YET in this sample since this HPL oil has plenty of TBN left.

You missed me here. The oil itself at 15K has likely had some oxidative thickening going on so that has countered the drop in viscosity from the addition of fuel in terms of the viscosity of the oil. You can't add fuel and not see a drop in viscosity unless that has happened.

 

[fantastic]

You missed me here. The oil itself at 15K has likely had some oxidative thickening going on so that has countered the drop in viscosity from the addition of fuel in terms of the viscosity of the oil. You can't add fuel and not see a drop in viscosity unless that has happened.

I understand. I didn't think about it that way.

 

[buster]

Just for a reference:
9/21/21 was Castrol Edge 0w40
01/23/22 was M1 0w30 AFE
10/12/22 was M1 0w40 FS

liqui moly mos2 additive every oil change (except HPL) since new

 

[TiGeo]

Just for a reference:
9/21/21 was Castrol Edge 0w40
01/23/22 was M1 0w30 AFE
10/12/22 was M1 0w40 FS

liqui moly mos2 additive every oil change (except HPL) since new

In before someone says the MoS2 is clumped in your oil pan.

 

[Highboy]

I am surprised with such a high TBN after that many miles.

He also added about 2 quarts of make up oil could’ve helped keep the TBN higher.

 

[TiGeo]

He also added about 2 quarts of make up oil could’ve helped keep the TBN higher.

This.

 

[buster]

This is an engine where throwing a boatload of AW additives at it won't' make a difference. The results are consistent across the board.

 

[Titan]

If I'm not mistaken, HPL has a little higher Silicon than many other oils...so, that Silicon may not be from your air box issue. Thanks for posting.

 

[TiGeo]

If I'm not mistaken, HPL has a little higher Silicon than many other oils...so, that Silicon may not be from your air box issue. Thanks for posting.

The Euro version (5W40) has ~10ppm Si in the VOA.

 

[mt23]

In before someone says the MoS2 is clumped in your oil pan.

In before I cant respond that there have been no clumps in any pan or engine I've torn down with mos2 use. I've seen it stick to preexisting varnish and deposits giving the impression that the varnish or deposit is all mos2, but not actually an only mos2 clump

 

[TiGeo]

In before I cant respond that there have been no clumps in any pan or engine I've torn down with mos2 use. I've seen it stick to preexisting varnish and deposits giving the impression that the varnish or deposit is all mos2, but not actually an only mos2 clump

Of course there isn't b/c unless you let your engine sit for 6 mos and don't drive it, it doesn't do that but folks here are all scared of it b/c of stories....

 

[mt23]

That's great you went to inspect the poor seal on the air box & found the culprit. This is a very good report w/the fuel not doing any harm that we can tell from this UOA.

I had intake off for some maintenance during the previous oil change. I noticed silicon was higher after last uoa and assumed there were no issues with intake. Remembering in the back of my mind that silicon was up, not long ago I noticed the airbox wasnt flush and true even though latched. We'll see if silicon changes as a result of adjusting the airbox completely true and flush