[Trey T]

LOL, got tired of thousands of comments, nearly as many posts, and the YEARS of no one agreeing on that topic, and almost no one considering that maybe... just maybe... engine manufacturers know what happens to oil over time, under load and when it heats up.

This isn't a contentious issue when then topic is discussed from a technical basis, instead of policy (e.g. user manual which is polished by legal folks).

This is a discussion board, so you can choose to discuss it but throw the rules at the wall... lol. Knowledge is power!

 

[Robert.Mauro]

This isn't a contentious issue when then topic is discussed from a technical basis, instead of policy (e.g. user manual which is polished by legal folks).

This is a discussion board, so you can choose to discuss it but throw the rules at the wall... lol. Knowledge is power!

No one on the thread has discussed anything technical regarding using the wrong oil in the Ascent FA24F. There's literally not a single such post. There's nothing at all technical about making up conclusions based on zero data. That's just rampant speculation. Zero data, zero tear downs. Zero idea if Subaru's engineers are too stupid to understand oil viscosity, shearing and aging/breakdown.

But as I said, feel free to continue.

 

[bluzed91]

I for one am not calling anyone stupid. I found and posted a Used Oil Analysis of a an Ascent that used 0w20 oil and in that report it showed that the oil thinned below the 0w20 threshold. Knowing this I would feel more comfortable running a slightly thicker 0w30 that would thin into the 0w20 range for the duration of the oci. Regardless it’s a personal choice no one has to join me but I did provide some evidence of my reasoning. Besides how many run different tires or wheels not original to their ascents? Surely Subaru specified the Falken tires and the factory wheels. We change those out all the time. I am not calling engineers stupid.besides manufacturers can change their minds on their specs on oil requirements like ford did going from 5w20 to 5w30.

 

[Packard8]

I for one am not calling anyone stupid. I found and posted a Used Oil Analysis of a an Ascent that used 0w20 oil and in that report it showed that the oil thinned below the 0w20 threshold. Knowing this I would feel more comfortable running a slightly thicker 0w30 that would thin into the 0w20 range for the duration of the oci. Regardless it’s a personal choice no one has to join me but I did provide some evidence of my reasoning. Besides how many run different tires or wheels not original to their ascents? Surely Subaru specified the Falken tires and the factory wheels. We change those out all the time. I am not calling engineers stupid.besides manufacturers can change their minds on their specs on oil requirements like ford did going from 5w20 to 5w30.

Oil & filters are cheap. It costs me around $26 to do a DIY change. Kirkland DEXOS Gen2, SN+ 0W20 full syn oil ($20 for a 5qt jug) & OEM blue filters ($6 ea). I do 3K mile OCIs, enter them in the mysubaru app, save receipts, and I never worry about thermal degradation, shear, fuel dilution, etc, etc.

Cheap insurance and I sleep well at night.

YMMV

 

[Trey T]

Just curious...what are the rod & main brg clearances on the FA24 Ascent engine? I'm more familiar with older iron where there was no "range" of acceptable clearances, just the one the factory spec'd. Are there other component considerations? Like hyd timing chain tensioners and VVT valve actuators (if equipt)?

I had a Ford truck with the Navistar DT444 engine with HEUI injectors that was very picky about the motor oil. The injectors are hydraulically actuated and if the oil didn't have the correct anti-foam additives the injectors would not operate properly. There may be other considerations than just brg clearances at play as to why Subaru specs a specific oil.

Ascent FA24 (2019+)
Con-rod 0.0010" - 0.0022"
Main 0.0005" - 0.0012"

WRX FA20F (2016+)
Con-rod 0.0007" - 0.0018"
Main 0.0004" - 0.0012"

BRZ FA20
Con-rod 0.0009" - 0.0022"
Main 0.0005" - 0.0012"

basically all of the FA variance has same/similar clearance but specified oil range of 0w20 to 0w40. But if you want to split hair, the WRX STi has tighter clearance range but uses thicker oil.

If y'all need bearing widths and related specs, I can post up later.

 

[Robert.Mauro]

I for one am not calling anyone stupid. I found and posted a Used Oil Analysis of a an Ascent that used 0w20 oil and in that report it showed that the oil thinned below the 0w20 threshold.

Never happened.

The Ascent uses:
ZERO to 20 weight. That's literally what the ZERO in ZERO-W-TWENTY means:

• ZERO W(inter)/(cold/sub-zero) to TWENTY (at 210°F) weight oil. With it ranging anywhere in between depending on temps.

Our engines don't necessarily run at the 20 side of things, btw. My Ascent's engine oil runs from 180's to mid 200's, unless I am doing crazy things. The 20 in 0W-20 is at 210°F. At 186°F, I'd expect my oil will be acting thinner. ALL THE WAY DOWN TO ZERO in cold weather, like during my Make-A-Wish trips into the frozen north.

• 16 IS between 0 and 20.
• THIRTY is NOT between 0 and 20 (eg: 0W-30 oil and 5W-30 oil).

Breaking down the 0W-20 code, “0” is the oil's viscosity at startup when the engine is cold, “W” stands for its winter certification, and “20” is the viscosity at higher temperatures. Lower numbers designate thinner, lower-friction oil.

Ascent FA24 (2019+)
Con-rod 0.0010" - 0.0022"
Main 0.0005" - 0.0012"

WRX FA20F (2016+)
Con-rod 0.0007" - 0.0018"
Main 0.0004" - 0.0012"

BRZ FA20
Con-rod 0.0009" - 0.0022"
Main 0.0005" - 0.0012"

basically all of the FA variance has same/similar clearance but specified oil range of 0w20 to 0w40. But if you want to split hair, the WRX STi has tighter clearance range but uses thicker oil.

I still don't understand the relevance - as I have said REPEATEDLY, the FA20F and FA20 are QUITE different than the FA24F in key ways.

We run a different turbo (well, the BRZ runs none), a very different tune, different oil plumbing, and a VASTLY different load factor (literally 3-4 times that of the other two).

You should not compare the lubrication requirements of the FA20F (much less the FA20) with the FA24F in the Ascent.

SHORT list of changes:

• pistons (shape, design - not just size)
• piston rings (again, not just size)
• connecting rods (beefier, structural design changes
• certain bearings
• oil journals
• oil plumbing
• turbo
• ENGINE LOAD (as much as 11,000 pounds vs a tiny fraction of that for the BRZ and WRX)

 

[Robert.Mauro]

Besides how many run different tires or wheels not original to their ascents? Surely Subaru specified the Falken tires and the factory wheels. We change those out all the time.

Sorry, but that's a poor and unrelated example/whataboutism. Some of us made sure our choices meet or exceed the factory choices. ALL of us can do that. For instance, my tires and wheels, even though they're 17", are an exact match for width and circumference of the OEM wheel/tire setup. Mine ALSO don't exceed the OEM wheel/tire weight.

So, that's different. And matchable.

• 0W-30 doesn't match 0W-20.
  Again, 30 is greater than 20. NONE of us can "adjust" for that. 0W-30 is 0W-30. Every "aged" and "diluted" oil post to date has shown the oil to be within the viscosity range selected by the engineers for the Ascent. You all are trying to fix a problem that literally doesn't exist, and in doing so, creating a problem. Subaru can and has denied warranty claims for these things, as I stated above - but that's your gamble. And your car. And your car loan/money. Feel free.
  
  
• My wheels and tires do match OEM specs.
  They're a matchable component. I spec'd out everything to make sure my choices wouldn't impact either car or warranty. And, guess what? During a warranty repair, they came into question, and were measured and weighed to make sure, otherwise, I had a warranty issue that wouldn't have been covered.

 

[Packard8]

Sorry, but that's a poor and unrelated example/whataboutism. Some of us made sure our choices meet or exceed the factory choices. ALL of us can do that. For instance, my tires and wheels, even though they're 17", are an exact match for width and circumference of the OEM wheel/tire setup. Mine ALSO don't exceed the OEM wheel/tire weight.

So, that's different. And matchable.

• 0W-30 doesn't match 0W-20.
  Again, 30 is greater than 20. NONE of us can "adjust" for that. 0W-30 is 0W-30. Every "aged" and "diluted" oil post to date has shown the oil to be within the viscosity range selected by the engineers for the Ascent. You all are trying to fix a problem that literally doesn't exist, and in doing so, creating a problem. Subaru can and has denied warranty claims for these things, as I stated above - but that's your gamble. And your car. And your car loan/money. Feel free.
  
  
• My wheels and tires do match OEM specs.
  They're a matchable component. I spec'd out everything to make sure my choices wouldn't impact either car or warranty. And, guess what? During a warranty repair, they came into question, and were measured and weighed to make sure, otherwise, I had a warranty issue that wouldn't have been covered.

I believe the Moss Magnusson Act states that a warranty can't be voided when using parts that meet or exceed the manufactures's specs. I use Kirkland 0W20 full syn oil, as it has the same API, SN+, DEXOS, etc ratings that Subaru specifies, and I buy it for as low as $3/qt when on sale. Same with tires, wheels, filters, etc. Brand name doesn't matter as long as mfg specs are met.

As long as Subaru specs 0W20 full syn, that's what I'll use. If & when they make a change, I will also. After paying $42K+ for the car, and another $2K for extended warranty coverage, it's just not worth the gamble for me to second guess what's in the owner's manual. YMMV

 

[Robert.Mauro]

Exactly, which is why my steering rack was covered, instead of denied, due to my choice of wheels and tires. Met or exceeded manufacturer requirements. BUT, they were required to make sure of that, before the warranty claim was approved.

 

[Packard8]

Exactly, which is why my steering rack was covered, instead of denied, due to my choice of wheels and tires. Met or exceeded manufacturer requirements. BUT, they were required to make sure of that, before the warranty claim was approved.
View attachment 19623

I wonder what the out-of-pocket cost of the steering rack would have been if not covered by SAS Gold Plus.

I had a Bosch injection pump replaced on a Ram/Cummins 5.9 by the FCA ESC. The service manager said it would have been over $4K if not covered. The savings paid for that contract, plus the one on the next truck I bought.

 

[Robert.Mauro]

I think around $1800? The rack is $1,266.23, and the labor isn't too bad.

 

[Trey T]

Never happened.

The Ascent uses:
ZERO to 20 weight. That's literally what the ZERO in ZERO-W-TWENTY means:

• ZERO W(inter)/(cold/sub-zero) to TWENTY (at 210°F) weight oil. With it ranging anywhere in between depending on temps.

Our engines don't necessarily run at the 20 side of things, btw. My Ascent's engine oil runs from 180's to mid 200's, unless I am doing crazy things. The 20 in 0W-20 is at 210°F. At 186°F, I'd expect my oil will be acting thinner. ALL THE WAY DOWN TO ZERO in cold weather, like during my Make-A-Wish trips into the frozen north.

• 16 IS between 0 and 20.
• THIRTY is NOT between 0 and 20 (eg: 0W-30 oil and 5W-30 oil).

Breaking down the 0W-20 code, “0” is the oil's viscosity at startup when the engine is cold, “W” stands for its winter certification, and “20” is the viscosity at higher temperatures. Lower numbers designate thinner, lower-friction oil.

I still don't understand the relevance - as I have said REPEATEDLY, the FA20F and FA20 are QUITE different than the FA24F in key ways.

We run a different turbo (well, the BRZ runs none), a very different tune, different oil plumbing, and a VASTLY different load factor (literally 3-4 times that of the other two).

You should not compare the lubrication requirements of the FA20F (much less the FA20) with the FA24F in the Ascent.

SHORT list of changes:

• pistons (shape, design - not just size)
• piston rings (again, not just size)
• connecting rods (beefier, structural design changes
• certain bearings
• oil journals
• oil plumbing
• turbo
• ENGINE LOAD (as much as 11,000 pounds vs a tiny fraction of that for the BRZ and WRX)

I'm really curious, Robert... what do you think oil clearance of the main bearing and connecting rod bearing means to you, in terms of viscosity? Please explain in the way that you know, prefer not from Google.

 

[Robert.Mauro]

You seriously don't understand what happens when an output shaft is under heavier load?

And regardless, you've still posted no Ascent specific data that shows why you should use out of spec thicker oil to lubricate THE ASCENT.

You're comparing a different engine, different turbo, and different use case as if it matters.

 

[RobertD]

Not a whole lot to add that Robert has not covered. I do find it interesting that it calls for 0w30 conventional oil and not synthetic oil in case no 0w20 synthetic is available.

 

[Packard8]

Not a whole lot to add that Robert has not covered. I do find it interesting that it calls for 0w30 conventional oil and not synthetic oil in case no 0w20 synthetic is available.

Interesting..... Without looking it up (lazy), do they still allow the full 6K OCI using the dino oil, or just as a temp/emergency limited use?

 

[Jim_in_PA]

Interesting..... Without looking it up (lazy), do they still allow the full 6K OCI using the dino oil, or just as a temp/emergency limited use?

I believe that was mentioned earlier in the thread...the 0w30 is only for "topping off" in the unlikely event 0w20 isn't available, not a full fill.

 

[Robert.Mauro]

Interesting..... Without looking it up (lazy), do they still allow the full 6K OCI using the dino oil, or just as a temp/emergency limited use?

Only emergency use, only to top off low fluid, only if the correct fluid isn't available.

That last one pretty much means "never allowed" for almost all of us. 😉

Never as a oil change alternative.

 

[RobertD]

Interesting..... Without looking it up (lazy), do they still allow the full 6K OCI using the dino oil, or just as a temp/emergency limited use?

The reason I found this interesting is because turbos are a bit harder on oils especially if you run the car (and turbo) hard. The temperatures are rather high and the rpms of the turbo are much higher than that of the engine inducing more oil shear stresses.

Before synthetic oils became the "norm" for turbo engines there were several turbo failures from conventional oils breaking down. I think that the evolution of the synthetic oils and well as advances in metallurgy has made turbos fairly reliable these days and that is why we are seeing so many of them on new cars now.

The aftermarket for pickup trucks with turbos on diesels in the 80s to the early 00's had all sorts of engine cool down timers that helped keep the oil in place until the turbo cooled down again. Back then turbos were thought to last less than 100k miles. Still many of the old-timers have a hard time believing turbos are really reliable because of they lived through the 80s turbos.

My long winded way of saying that I would not use any oil but what is recommended by the manufacturer and I would put conventional / dino oil in my car.

 

[Packard8]

The reason I found this interesting is because turbos are a bit harder on oils especially if you run the car (and turbo) hard. The temperatures are rather high and the rpms of the turbo are much higher than that of the engine inducing more oil shear stresses.

Before synthetic oils became the "norm" for turbo engines there were several turbo failures from conventional oils breaking down. I think that the evolution of the synthetic oils and well as advances in metallurgy has made turbos fairly reliable these days and that is why we are seeing so many of them on new cars now.

The aftermarket for pickup trucks with turbos on diesels in the 80s to the early 00's had all sorts of engine cool down timers that helped keep the oil in place until the turbo cooled down again. Back then turbos were thought to last less than 100k miles. Still many of the old-timers have a hard time believing turbos are really reliable because of they lived through the 80s turbos.

My long winded way of saying that I would not use any oil but what is recommended by the manufacturer and I would put conventional / dino oil in my car.

I've had a few turbo diesel trucks and "oil coking" used to be an issue back then if you didn't let the turbo cool down at idle. When approaching an interstate rest or fuel stop, it was common practice to downshift, engine brake and let cool air flow through the turbo. When dino oil sits on a hot, stationary turbo shaft it quickly turns to carbon. Synthetics thankfully eliminated the need to do so.

 

[Outback King]

Greetings folks, there is an email posted over at SubaruOutback.org from Subaru corporate where they clearly state that 0W30 grade synthetic oil is permissible to be used in the FA24F engine.

I for one plan to use Mobil 1 ESP 0w30 in my recently purchased 2025 Subaru Outback Wilderness as many have shared UOA data using that oil in that engine that has proven, excellent results.