2019 Subaru Ascent - Castrol Synthetic 0W-20 - 3,409 Mi OCI

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Feb 12, 2004
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This UOA is for my sister's 2019 Subaru Ascent. This OCI includes approximately 2k of highway miles for a heavily laden summer drive from WA to ID and back, with the remainder probably 30/70 city/highway. We drained it a bit earlier than normal in order to get the lab sample. Overall I think it's pretty good, and that her dealership is trying to rip her off.

TL DR: Sister went 12k on a previous OCI, dealer told her that her engine is damaged. This sample was drawn 6k miles after she was told that, and I think it refutes their claim. What do you think?

Here's the more detailed story for anyone interested:

She accidentally did about a 12k mile OCI from approximately 20k miles to 32k miles. She has been having the dealer where she bought it do her oil changes; according to them they use some type of Castrol synthetic 0W-20, but they were not specific as to the exact formula. When she was finally able to take it to her local dealer for an oil change they told her that her long OCI had caused leaking from the oil pan and probably done serious engine damage. They said that there were metal flakes visible in the used oil, and wanted to start doing expensive diagnostic procedures.

When she told me about it I thought that was absurd that a synthetic would fail that badly after 12k miles, considering that many manufacturers are recommending OCIs up to 10k. As far as driving styles, we are polar opposites - She's very cautious and doesn't use boost very often, so it's not as if she's hard on the engine.

I had her bring the car to me and I got it up on ramps. There is minor weeping from the oil pan gasket, nothing serious, but a little disappointing for what was at the time a 32k mile vehicle. We decided to do a UOA to find out the truth about the significant metal flakes she was told about. Due to scheduling issues the dealer did her next oil change at about 35k miles, then I did the 38k mile change where we drew this sample.

She's been monitoring the oil level closely since 32k miles and the oil level is remaining constant with no measurable changes.

I'd love to hear your thoughts.

Ascent 08.22.21 Oil Sample Result.jpg
 
She accidentally did about a 12k mile OCI from approximately 20k miles to 32k miles. She has been having the dealer where she bought it do her oil changes; according to them they use some type of Castrol synthetic 0W-20, but they were not specific as to the exact formula. When she was finally able to take it to her local dealer for an oil change they told her that her long OCI had caused leaking from the oil pan and probably done serious engine damage. They said that there were metal flakes visible in the used oil, and wanted to start doing expensive diagnostic procedures.

When she told me about it I thought that was absurd that a synthetic would fail that badly after 12k miles, considering that many manufacturers are recommending OCIs up to 10k. As far as driving styles, we are polar opposites - She's very cautious and doesn't use boost very often, so it's not as if she's hard on the engine.

These extended drain intervals should be seen as a best case scenario and do not apply to every single engine in every single circumstance for every single vehicle. You can read on any container of motor oil and see that the oil manufacturers recommend following the auto manufacturers' oil change recommendations.

The engine in the Subaru Ascent (FA24F TGDI) in its short history is known as an engine that is incredibly hard on oil (based on UOA data) and Subaru's normal 6000 mile oil change interval should be seen as a maximum interval for that engine. If you read the owners manual the majority of owners will likely fall under the 3000 mile severe service interval, it's not necessarily about what engine oil you use but rather has to do with the engine you are using it in.

Furthermore Subaru also specifies that oil consumption can be expected in these engines in the owners manual and I can only imagine what may have happened if the interval was 12,000 miles instead of 3000 to 6000 miles as recommended. Another factor is the oil filter, the Subaru OEM oil filter is not good for much more than 6000 miles of usage per Subaru so chances are that the engine was seeing unfiltered bypass oil on a regular basis. Subaru has also issued a TSB for carbon buildup for these engines in recent times under normal usage circumstances, running extended oil change intervals is only going to further contribute to that known issue.

Moral of the story is that I would have to agree with the dealership that running that specific vehicle for 12,000 miles between oil changes is problematic at the very least and quite likely did cause serious damage. Doing this likely voided any warranty on that vehicle as well.
 
I would stick with the shorter OCIs as others have mentioned.

A weeping oil pan gasket is not a sign of engine damage. Did they tighten it up below? Keep an eye on that. It sounds like they tried to put the fear of God on her for running the oil too long and it was interpreted as she had killed the motor.


My usual phrase on these stories is that a synthetic oil will run a long time but only if the motor allows it.
 
How does it run?

The UOA does look really good.

There's not a lot you can do at this point. 12,000 in most cars wouldn't be the end all. I recently went 15,000 on my Saab when life got crazy. It runs beautifully.

I'd just keep doing those regular oil changes and try to enjoy the car. Is the pan still leaking?
 
JMO; Not sure what "expensive diagnostics" are warranted; what exactly is broken @ this point.

I don't know what specific diagnostics a dealership would do either but since 2013 Subaru has had an issue with oil consumption that they have acknowledged and even gone so far as writing about using suggestive language in every late model owners manual. This primarily arises from oil change intervals beyond 6000 miles.

Mind you that this is a TGDI engine as well with a track record of being very hard on oil. What is up with BITOG on this one? I feel like if a dealership weren't involved in the story of this vehicle the BITOG hivemind would normally be flipping out about a Subaru TGDI running an interval this long. BUT since a dealership is interjected into the story and they've stated their position the inclination seems to be to oppose the dealership and maybe even common sense.
 
This is squarely in the "what's done is done"

I acknowledge the history and special maintenance required for this engine, but the OP is taking prudent measures; I don't see the dealer "fixing anything" as this point, just raising the anxiety of the owner and possibly the bottom line of the dealer. This is a one time oversight, not a 120K mile history of neglect.
 
This is squarely in the "what's done is done"

I acknowledge the history and special maintenance required for this engine, but the OP is taking prudent measures; I don't see the dealer "fixing anything" as this point, just raising the anxiety of the owner and possibly the bottom line of the dealer. This is a one time oversight, not a 120K mile history of neglect.

That is fine, I don't think that anyone can undo damage that contributes to what will now likely be a chronic oil consumption issue that will develop with this engine as well as other additional problems likely to occur.

3000 mile oil change intervals is what I recommend for this engine even if brand new and I have a few dozen UOA reports to refer to for this engine that inform my recommendation.
 
To help assess this,

How is the fuel mileage - did it take any hit after the supposed "damage".

How is the perceived engine noise and performance? Worse than typical?

Also cut open the filter - your abnormal "wear metals" will be in there NOT in the UOA.

Too bad you couldn't cut open the filter the dealer did an oil change on.

I don't know how she "accidentally" went 12K did someone forget to reset the Maintenance minder?
That could be a $10,000.00 accident.
 
That is fine, I don't think that anyone can undo damage that contributes to what will now likely be a chronic oil consumption issue that will develop with this engine as well as other additional problems likely to occur.

3000 mile oil change intervals is what I recommend for this engine even if brand new and I have a few dozen UOA reports to refer to for this engine that inform my recommendation.
I don't believe that there is any lasting damage, based on the facts that we have an excellent UOA, the engine is running normally (by NVH measures) and there has been no oil level movement on the dipstick over the last 6k miles. We've been paying close attention to the oil level, as increased consumption was one of my major concerns.

I unfortunately don't have details on what work the dealer wanted to do, only that it was going to be diagnostic and expensive.

I think my sister has been helped by the fact that she does a good amount of highway driving and is a really gentle driver. I know that 5k miles on my 2018 WRX with it's 2.0L version of this engine shears M1 0W-40 down to a 30 weight, but that car gets a lot more...exercise. I can't imagine what would happen if I tried to run 12k miles like that!
 
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To help assess this,

How is the fuel mileage - did it take any hit after the supposed "damage".

How is the perceived engine noise and performance? Worse than typical?

Also cut open the filter - your abnormal "wear metals" will be in there NOT in the UOA.

Too bad you couldn't cut open the filter the dealer did an oil change on.

I don't know how she "accidentally" went 12K did someone forget to reset the Maintenance minder?
That could be a $10,000.00 accident.
I don't believe that she was tracking fuel economy before, but it would be a good idea to start now. We won't have a before and after record, but if she hits the range we'd expect on an undamaged engine that would be one less thing to worry about.

She's had no complaints about unusual engine noise or vibration.

I would imagine that if the oil filter is going to catch wear metals before they got into the UOA, that it would also have caught the metal flakes the dealer said they saw. I'm not inclined to believe this particular dealer mechanic, considering that he's also trying to blame pan gasket weeping on the long OCI.

I won't go into personal specifics, but she has an absolutely hellish schedule, so I don't blame her for going over once. You're right, it could be an incredibly expensive accident!

We've already found a very well reviewed Subaru shop near her place, so she'll likely either start doing changes there. I may do some as well, so I really doubt we'll see any more extended OCIs.
 
The purpose of UOA is not the state of engine, but oil. There are engines on death bed that will provide good “wear numbers.”
Correct.

Take it to a different dealer and have the "weep" repaired under warranty.
Agreed.

I don't believe that there is any lasting damage, based on the facts that we have an excellent UOA, the engine is running normally (by NVH measures) and there has been no oil level movement on the dipstick over the last 6k miles. We've been paying close attention to the oil level, as increased consumption was one of my major concerns.
Unfortunately none of those items are conclusive on the engine's condition. The long OCI probably left behind some amount of excessive varnish/sludge and possibly caused excessive wear. A UOA of the current fill only shows the condition of the current oil. If the current fill was changed at a normal interval, then it will naturally show a normal amount of wear.
 
Correct.


Agreed.


Unfortunately none of those items are conclusive on the engine's condition. The long OCI probably left behind some amount of excessive varnish/sludge and possibly caused excessive wear. A UOA of the current fill only shows the condition of the current oil. If the current fill was changed at a normal interval, then it will naturally show a normal amount of wear.
Use Mobil1 0W40FS!
 
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