Fuel in oil

[N. J. Jim]

Subaru’s aren‘t as reliable as they used to be, so do your research. Some models/ years have a significant parasitic battery drain issue.

I had a 2011Subaru Outback good car but you couldn't keep low beam headlight bulbs in it. I had the car for almost 9 years and changed 6 low beam bulbs. My girlfriend has the same year and I finally put LED bulbs in hers a couple of years ago, so far their still holding out. Subaru ended up changing bulbs for customers for awhile at no charge but they were standard bulbs that were like having 2 candles for headlights.

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[JasonTremor]

The Subarus are the opposite, they use oil instead of making it. They historically used so much that Subaru changed the oil change interval from 7500 miles to 5000 miles to prevent the customer from seeing the low oil light. They blamed theirs on low tension piston rings.

 

[N. J. Jim]

The Subarus are the opposite, they use oil instead of making it. They historically used so much that Subaru changed the oil change interval from 7500 miles to 5000 miles to prevent the customer from seeing the low oil light. They blamed theirs on low tension piston rings.

I had 96 thousand on mine wasn't too bad on oil about a half quart to three quarters of a quart in the 5000 mile oil change interval.

 

[JasonTremor]

I had 96 thousand on mine wasn't too bad on oil about a half quart to three quarters of a quart in the 5000 mile oil change interval.

Mine was a 2014 Forester. 2-2.5 quarts every 5k miles. Got a new engine block replacement at 25k miles after two oil studies. New engine used same amount of oil and I eventually got them to buy it back.

I've heard they eventually resolved the issue in later years, but never tried another one.

 

[JustSteve]

Someone keeps posting on TTAC about the oil dilution issue on every Ford article. Also drops a link to this forum.

 

[JasonTremor]

Got my oil analysis back today. I forgot to include my 5w30 oil weight so they didn't include the sus viscosity (55-63) or cst viscosity (8.8-11.3) acceptable ranges on the report.

Oil level at about 34 miles was at max fill hole and at 1960 miles it was 3/8" above max fill. Recovered about 6.75 quarts on the drain and lost a little. When I refilled engine with 6.25 quarts, it was at max fill hole. So somewhere between .5 and .75 quart will bring it from max fill hole to 3/8" above max fill.

 

[JDG]

Got my oil analysis back today. I forgot to include my 5w30 oil weight so they didn't include the sus viscosity (55-63) or cst viscosity (8.8-11.3) acceptable ranges on the report.

Oil level at about 34 miles was at max fill hole and at 1960 miles it was 3/8" above max fill. Recovered about 6.75 quarts on the drain and lost a little. When I refilled engine with 6.25 quarts, it was at max fill hole. So somewhere between .5 and .75 quart will bring it from max fill hole to 3/8" above max fill.

My first oil sample analysis on my 21 Tremor had nearly identical results to yours (see attached).

My fuel percentage was ~1% higher with a flashpoint of 310F.

I just sent off another oil sample to the lab after another 6.3K miles (8,910 Miles on Vehicle). The second sample is Amsoil Signature 5W-30.

Hopefully fuel is down somewhat.

Edit: Something I have been thinking about that I haven't seen mentioned as well, is that if wear metals are not high, despite the lower viscosity oil (from fuel dilution), this isn't really an issue as far as engine longevity is concerned. My theory is that given the 10R80 transmission in this vehicle, the engine is being asked to run at much lower RPM's compared to the other vehicles it is found in (i.e. Focus RS, Mustang). Lower RPM is more conducive to the fuel not atomizing and therefore washing down the cylinder walls into the oil. It is also conducive to lower engine temperature making it harder for the fuel to vaporize out of the oil (see Honda 1.5L oil dilution issues).

This next oil analysis will be interesting for me because I did a lot of miles, both highway and back roads, and have been pretty regularly beating on the truck (similarly to my Fiesta ST - which never saw >1% fuel in oil).

 

[JasonTremor]

My first oil sample analysis on my 21 Tremor had nearly identical results to yours (see attached).

My fuel percentage was ~1% higher with a flashpoint of 310F.

I just sent off another oil sample to the lab after another 6.3K miles (8,910 Miles on Vehicle). The second sample is Amsoil Signature 5W-30.

Hopefully fuel is down somewhat.

Edit: Something I have been thinking about that I haven't seen mentioned as well, is that if wear metals are not high, despite the lower viscosity oil (from fuel dilution), this isn't really an issue as far as engine longevity is concerned. My theory is that given the 10R80 transmission in this vehicle, the engine is being asked to run at much lower RPM's compared to the other vehicles it is found in (i.e. Focus RS, Mustang). Lower RPM is more conducive to the fuel not atomizing and therefore washing down the cylinder walls into the oil. It is also conducive to lower engine temperature making it harder for the fuel to vaporize out of the oil (see Honda 1.5L oil dilution issues).

This next oil analysis will be interesting for me because I did a lot of miles, both highway and back roads, and have been pretty regularly beating on the truck (similarly to my Fiesta ST - which never saw >1% fuel in oil).

The lower rpm could definitely come into play, but with direct injection, it should be injecting fuel at near the top of the compression stroke as opposed to near the bottom of the compression stroke like a port fuel injection engine does. I plugged in a SCT X4 the other day to data log some of the fuel and spark related data. I can read fuel rail pressure and am curious what residual pressure should be after shutting off the engine. Residual pressure readings could tell me if the pressure is leaking down after a drive cycle in an unexpected way.

Curious to see if your next analysis comes back better. I saw one person in the bronco 6g forum had examples of where is fuel in oil percentage decreased on the second oil change.

 

[VegasRanger]

Got my oil analysis back today. I forgot to include my 5w30 oil weight so they didn't include the sus viscosity (55-63) or cst viscosity (8.8-11.3) acceptable ranges on the report.

Oil level at about 34 miles was at max fill hole and at 1960 miles it was 3/8" above max fill. Recovered about 6.75 quarts on the drain and lost a little. When I refilled engine with 6.25 quarts, it was at max fill hole. So somewhere between .5 and .75 quart will bring it from max fill hole to 3/8" above max fill.

Mine was also at 2.8 but at the 10,000 miles mark.

 

[Doc]

2.8 too much …

 

[JasonTremor]

I asked Blackstone about the viscosity and their response was it had specs of 5w20 at the viscosity shown.

 

[JDG]

I asked Blackstone about the viscosity and their response was it had specs of 5w20 at the viscosity shown.

That's good info. It looks like the OEM spec for Focus RS is 5W-50 while Explorer, Mustang, etc. are 5W-30 like the ranger. If my next sample shows anything above 2% I may go up to a 5W-40 to account for the dilution and allow me to run the true 8-10K mile interval.

I am finding the same thing with my report, it looks like the viscosity after 2500 miles was right in the range for 5W-20.

 

[Dgc333]

That's good info. It looks like the OEM spec for Focus RS is 5W-50 while Explorer, Mustang, etc. are 5W-30 like the ranger. If my next sample shows anything above 2% I may go up to a 5W-40 to account for the dilution and allow me to run the true 8-10K mile interval.

I am finding the same thing with my report, it looks like the viscosity after 2500 miles was right in the range for 5W-20.

FWIW, the 2.3 Ecoboost in the High Performance Package Mustang recommends 5w-50 and the standard 2.3 Ecoboost in the Mustang recommends 5w-50 when tracking the car.

 

[VegasRanger]

2.8 too much …

Some people here think that 2.8 seems normal for a DI engine with a turbo. I don't know.

I will send another sample at the 15K mark. I switched from Castrol to Pennzoil Ultra Platinum oil just to see if that makes any difference. I also make an attempt to floor it when I get on the freeway every once and a while. I'll see what difference this makes if any when my send my next sample in. The only thing that puts me at ease somewhat, was the fact that blackstone says my engine seems to be wearing really good and no signs of any metals, etc. in the oil.

 

[Doc]

FWIW, the 2.3 Ecoboost in the High Performance Package Mustang recommends 5w-50 and the standard 2.3 Ecoboost in the Mustang recommends 5w-50 when tracking the car.

5w50…HPP

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