Fuel Dilution: 2022 Subaru Crosstrek FB20D 2,774mi OCI Schaeffer Supreme 9000 0W-20

[Artem]

I'm done with Schaeffer's. Great stuff but pricey and hard for me to get now. I have three 5 qt jugs of Pennzoil UP 0W-20 on the shelf so in 9,000mi when these three jugs are gone, I think I'll switch to Pennzoil UP 5W-30 and see how that looks after 3,000mi. I'm thinking much better! I agree wear metals are looking good.

What exactly will “look better” with a thicker oil? Fuel dilution certainly won’t be going anywhere.

It’s not like you’re suffering from low viscosity or extra wear as a result of the w20, even with the splash of Petrol in there for flavor.

 

[Artem]

What confuses me is that with this oil sample, there was more highway driving than the other previous ones and the fuel dilution went up! Ocean trip, several 70mi round trip highway trips to the airport and back. Can someone explain that one to me?

Well isn’t it obvious…? Easy highway cruising isn’t getting your block HOT ENOUGH to burn off anything. Try pounding on it and giving ‘er the good ol’ Italian Tune-Up and redline it 4-5 times by blasting up a highway On Ramp (then exit at the next ramp and redline it back the other way)

Then go home and change the oil. Now THAT will burn off some Octane for ya.

Your granny cruising ain’t cutting it.

 

[dezlpwr]

Well isn’t it obvious…? Easy highway cruising isn’t getting your block HOT ENOUGH to burn off anything. Try pounding on it and giving ‘er the good ol’ Italian Tune-Up and redline it 4-5 times by blasting up a highway On Ramp (then exit at the next ramp and redline it back the other way)

Then go home and change the oil. Now THAT will burn off some Octane for ya.

Your granny cruising ain’t cutting it.

It's a 6 spd manual and I get it up to 5k often when shifting, plus as I mentioned, I did take a road trip with sustained speeds of 70-80 mph. I'm sorry, but I think that should be sufficient?

 

[dezlpwr]

What exactly will “look better” with a thicker oil? Fuel dilution certainly won’t be going anywhere.

It’s not like you’re suffering from low viscosity or extra wear as a result of the w20, even with the splash of Petrol in there for flavor.

Viscosity will be closer to that of a 20WT with all the fuel dilution was my thinking. Is that flawed thinking?

 

[kschachn]

There is no substitute for grade when discussing dilution, unless you’re changing the oil at a frequent rate. Dilution is dilution.

 

[kschachn]

Well isn’t it obvious…? Easy highway cruising isn’t getting your block HOT ENOUGH to burn off anything. Try pounding on it and giving ‘er the good ol’ Italian Tune-Up and redline it 4-5 times by blasting up a highway On Ramp (then exit at the next ramp and redline it back the other way)

Then go home and change the oil. Now THAT will burn off some Octane for ya.

Your granny cruising ain’t cutting it.

Octane?

And not all the fuel dilution will be eliminated. For one thing it’s occurring at a constant rate.

 

[dezlpwr]

Octane?

And not all the fuel dilution will be eliminated. For one thing it’s occurring at a constant rate.

No but what I'm saying is that compared to the previous two oil samples, this last one with more fuel dilution had way more high speed highway driving. Why would that be? Shouldn't it be the opposite? The only thing I can think of is this oil was in the engine during the colder temps of winter. Cold is relative though in the Pacific Northwest.

 

[kschachn]

It depends upon the reason for the fuel dilution.

 

[OVERKILL]

Is OAI a reputable lab when it comes to fuel dilution testing? I know some labs just guesstimate fuel dilution from flash point which is not accurate.

Looks like OAI uses GC, so that should be reliable, I'd think.

OAI is Polaris, just sold as a private label through AMSOIL. Think of AMSOIL as a Polaris reseller, they have no stake in the lab, just resell the service. And yes, OAI/Polaris uses GC for fuel, so it's extremely accurate.

 

[bluesubie]

Fuel dilution isn’t as bad as it is in the DIT’s. Longer drives do not always burn off fuel in a DI engine and it’s doubtful that fuel would be lower with a shorter OCI IMO.

 

[Artem]

No but what I'm saying is that compared to the previous two oil samples, this last one with more fuel dilution had way more high speed highway driving. Why would that be? Shouldn't it be the opposite? The only thing I can think of is this oil was in the engine during the colder temps of winter. Cold is relative though in the Pacific Northwest.

Like I said… steady highway cruising doesn’t build up enough heat to really burn off anything. You have to pound on it and really get the engine temps up.

Colder weather does play a role in more fuel dilution as well.

Seems everything is stacked against you.

 

[dezlpwr]

Fuel dilution isn’t as bad as it is in the DIT’s. Longer drives do not always burn off fuel in a DI engine and it’s doubtful that fuel would be lower with a shorter OCI IMO.

How is that possible? The longer the oil is in use, wouldn't the percentage of fuel in the oil continue to build up/increase until the oil is changed?

Like I said… steady highway cruising doesn’t build up enough heat to really burn off anything. You have to pound on it and really get the engine temps up.

Colder weather does play a role in more fuel dilution as well.

Seems everything is stacked against you.

Ok... Taking it up to 5000 RPMs frequently out of a 6000rpm redline is not pounding on it? In that case I guess I'll live with the dilution and change the oil frequently as I'm doing. I don't need to blow up the engine in an effort to bring the fuel dilution down. I did notice that with previous UOAs, fuel dilution was lower by 1% during the warm weather months which makes sense.

 

[dezlpwr]

Fuel dilution isn’t as bad as it is in the DIT’s. Longer drives do not always burn off fuel in a DI engine and it’s doubtful that fuel would be lower with a shorter OCI IMO.

How does that compute? Wouldn't fuel dilution increase in the oil the longer it is ran? More time to accumulate in the oil I would think.

 

[Quattro Pete]

Even if you can manage to burn off the fuel, wouldn't the oil viscosity still be lower since contact with fuel permanently damages the oil?

Id probably just run higher grade oil to give myself more of a buffer, if that's a concern.

 

[Eddie]

I see the WEAR VALUES are low, so I don't think you have any problems with what you are doing. WEAR values are the important metric here, more so than the fuel%. Ed

 

[kschachn]

I see the WEAR VALUES are low, so I don't think you have any problems with what you are doing. WEAR values are the important metric here, more so than the fuel%. Ed

But no one has posted actual wear values.

 

[Eddie]

The wear values are shown in #1

 

[kschachn]

The wear values are shown in #1

Actually what is needed is the results of ASTM D6984-18.

 

[ARCOgraphite]

Despite Subaru's 6,000mi OCI recommendation, I will continue to do 3,000mi OCIs as long as fuel dilution continues. I'd hate to see the fuel dilution at 6,000mi if it is already flagged under 3,000mi. I just switched to Pennzoil Ultra Platinum 0W-20. It is easier for me to obtain than the Schaeffer. That obviously won't affect the fuel dilution. Vehicle is rarely idled, and sees very few short trips. 50/50 mix of highway and city driving. Titanium has been confirmed to be in the "old formula" Schaeffer oil that I have been using. They no longer use titanium in their new formula 0W-20 oil.

Sad to see my wife's otherwise fantastic '23 Crosstrek- which gets driven far and fast at well over 3000 rpm ( 6m trans) - is diluting, the oil looks and smells terrible. The engine is so darned noisy when warmed up it sounds like its going to throw a rod. I'm doing the next and 10w30 going in there. Minimise the VM oading and have a thicker base oil. Those super narrow FB crank bearings cant handle a low moft.

I Hate being a guinea pig for unproven tech. Whats the benefit here? None I see other than some more power with the (absurdly) high compression and subsequent OVER fueling. - Ken

 

[Quattro Pete]

Anyone tried oil extractor on this engine? Does it get most of the oil out?