2021 Subaru Outback 2.5L / Amsoil OE 0w-20 2.8k miles

[Nuclear_42]

Here's my 2.8k sample on my 2.5NA 21 Subaru Outback. I used a regular Wix filter. Viscosity is on the lower side of the range. I'm happy with the results and will change the current oil around 3-3.5k miles. I spoke over the phone with the lab about the fuel dilution. Subaru recommends 6k mile/ 3k mile severe svc intervals. The tech noted 5-6k mile runs are ok. Due to 5% being very common on newer DI cars. This Subaru sees 4 mile round trip daily work commutes and highway 1-2x a week 80% city/ 20% hwy 6-7k mile annually. I think 3-3.5k spring/ fall oil changes should be fine with Amsoil OE.

Here's my previous run results with Amsoil Signture 0w-20 for reference:

https://bobistheoilguy.com/forums/t...gnature-0w-20-4-9k-miles.366201/#post-6412949

 

[fantastic]

Other than fuel it doesn't appear too bad. 5% is max I would want to see in a gasoline engine. You'll find out what your sub does and adjust mileage from there. It's a shame though that these excessive fueled engines can ruin a longer run on expensive oil. Thanks for sharing.

 

[bluesubie]

Hey I was right when I said there wouldn’t be much difference in fuel dilution with a shorter OCI.

 

[Oliveoil2]

Looks like you have an injector leaking at 300k. This is a good use of a UOA!

 

[SubieRubyRoo]

It's a shame though that these excessive fueled engines can ruin a longer run on expensive oil.

It’s not so much “excessively fueled” as it is “really high pressure fuel, atomized very finely, and introduced just before ignition starts the party”…

Because the fuel is injected in the combustion chamber and not sucked into it when already mixed with air, there is more piston top/chamber wetting, and liquid fuel doesn’t burn. Then this fuel gets on the cylinder walls and makes it past the rings. Voila, higher fuel dilution and better mileage.

 

[fantastic]

It’s not so much “excessively fueled” as it is “really high pressure fuel, atomized very finely, and introduced just before ignition starts the party”…

Because the fuel is injected in the combustion chamber and not sucked into it when already mixed with air, there is more piston top/chamber wetting, and liquid fuel doesn’t burn. Then this fuel gets on the cylinder walls and makes it past the rings. Voila, higher fuel dilution and better mileage.

Very good information.

 

[Artem]

Looks like you have an injector leaking at 300k. This is a good use of a UOA!

Huh? at first I was confused and wanted to ask what you’ve been smoking but then I went and looked closer at the report.

 

[Impatient]

Sorry to bump this, but a (female) friend just bought one of these (2021 Outback NA, low mileage). She probably won’t listen to me, but I would like to advise her on oil changes. She lives in N. Tx, but often travels to New Mexico (Santa Fe & Gallop, maybe even in winter…of course, that’s not N Dakota).

I doubt she’ll buy into using Amsoil, but what do y’all think would be good “mainstream” oil and OCI to recommend? I’m thinking a thin 0w30…and she might object to short OCI’s given she’s coming from a 2012 v6 Tacoma…which I assume had “low” oil requirements.

I might buy her a UOA (from OA) someday to see if her new DI Subaru has similar fuel issues to @Nuclear_42 . I hope it doesn’t.

 

[Triple_Se7en]

Frequent oil changes (3k) using a thicker 5w30. Used filter can remain on, for a 2nd OCI.
If the female must penny-pinch, Supertech Syn or similar priced, will do.

 

[Impatient]

I’ll give her your contact info, and you can convince her to do 3k OCI’s. But, yeah, if Nuclear’s results are common, she better do something other than take it to Jiffy Lube once every 7k for some bulk 0w20.

Somewhat in line with your suggestion, I was thinking a thin xw-30, and yeah, maybe the QSFS from Walmart could work, though I didn’t like that stuff in my older Turbo EJ (hers is not Turbo, FB??). I got distracted, didn’t get around to it, but was thinking something with an HTHS of 2.9 or above. I haven’t been keeping up with M1, Castrol, Pennzoil etc 0w30’s (except the heavy Euro’s with 3.5 HTHS).

 

[Nuclear_42]

I’ll give her your contact info, and you can convince her to do 3k OCI’s. But, yeah, if Nuclear’s results are common, she better do something other than take it to Jiffy Lube once every 7k for some bulk 0w20.

Somewhat in line with your suggestion, I was thinking a thin xw-30, and yeah, maybe the QSFS from Walmart could work, though I didn’t like that stuff in my older Turbo EJ (hers is not Turbo, FB??). I got distracted, didn’t get around to it, but was thinking something with an HTHS of 2.9 or above. I haven’t been keeping up with M1, Castrol, Pennzoil etc 0w30’s (except the heavy Euro’s with 3.5 HTHS).

I made the switch to regular Mobil 1 Advanced fuel economy 0w-30. REGULAR 0w-20 is fine but shouldn't exceed 3,000 miles. If possible she can request 5w-30 when she gets the oil changed. I'd feel more comfortable doing 3-5k max if 5w-30 is being used.

 

[Impatient]

I made the switch to regular Mobil 1 Advanced fuel economy 0w-30. REGULAR 0w-20 is fine but shouldn't exceed 3,000 miles. If possible she can request 5w-30 when she gets the oil changed. I'd feel more comfortable doing 3-5k max if 5w-30 is being used.

I was trying to see if you did a UOA on the M1.

 

[SubieRubyRoo]

Fastest easiest cheapest way: get her on Pennzoil Euro L 5w30 every 5k. Use Fram Endurance 7317 and change every other OCI.

 

[buster]

I’ll give her your contact info, and you can convince her to do 3k OCI’s. But, yeah, if Nuclear’s results are common, she better do something other than take it to Jiffy Lube once every 7k for some bulk 0w20.

Somewhat in line with your suggestion, I was thinking a thin xw-30, and yeah, maybe the QSFS from Walmart could work, though I didn’t like that stuff in my older Turbo EJ (hers is not Turbo, FB??). I got distracted, didn’t get around to it, but was thinking something with an HTHS of 2.9 or above. I haven’t been keeping up with M1, Castrol, Pennzoil etc 0w30’s (except the heavy Euro’s with 3.5 HTHS).

Off the shelf I'd use Mobil 1 EP 5w/10-30 or EDGE EP 5w30/10w30. Boutique - Amsoil/HPL.

 

[fantastic]

I’ll give her your contact info, and you can convince her to do 3k OCI’s. But, yeah, if Nuclear’s results are common, she better do something other than take it to Jiffy Lube once every 7k for some bulk 0w20.

Somewhat in line with your suggestion, I was thinking a thin xw-30, and yeah, maybe the QSFS from Walmart could work, though I didn’t like that stuff in my older Turbo EJ (hers is not Turbo, FB??). I got distracted, didn’t get around to it, but was thinking something with an HTHS of 2.9 or above. I haven’t been keeping up with M1, Castrol, Pennzoil etc 0w30’s (except the heavy Euro’s with 3.5 HTHS).

Mobil AFE would be a thin 0w-30.

 

[Nuclear_42]

I was trying to see if you did a UOA on the M1.

I sent a sample actually on Friday with M1 AFE 0w-30 on 2.8k miles. Should have the results by the end of the week.

 

[Nuclear_42]

Off the shelf I'd use Mobil 1 EP 5w/10-30 or EDGE EP 5w30/10w30. Boutique - Amsoil/HPL.

Fastest easiest cheapest way: get her on Pennzoil Euro L 5w30 every 5k. Use Fram Endurance 7317 and change every other OCI.

I don’t want to light off a oil filter fire cracker. However as you may already know it’s important to stick with filters in the 20-30 psi range on these Subarus. Or else you run the risk of bypassing oil during acceleration and high speeds.

 

[Impatient]

i better stay away from the filter rabbit hole, as I have opinions…the good news for me is I can get Tokyo Roki filters for my 3.6 any day from the dealer. For the new FB motors, I have no clue.

Regarding oil itself, and given she’s not a hooner (that I know of), I think the balancing act is getting her to change the oil at least per Subaru recommended interval, and since that is way longer than @Nuclear_42 was doing with his Amsoil UOA’s, maybe going up a grade, as Nuclear did. I do know she will expect this thing to last well into mid 100k range (like 150k)…which is common with Subies, if they are maintained. But then, she freaked out about her Tacoma before then…and aren’t those supposed to be 300k vehicles? I’m leaning toward recommending a common oil with at least a 2.9 HTHS. Is that the wrong way to look at this? That would mean most xw30’s should qualify…such as the M1 AFE. Fuel will lower that, but that is why I would suggest at least 2.9. I need to find Gokhan’s spreadsheet…

I’m equally concerned she will listen to the “lifetime CVT fluid” claim.

 

[SubieRubyRoo]

I don’t want to light off an oil filter fire cracker. However as you may already know it’s important to stick with filters in the 20-30 psi range on these Subarus. Or else you run the risk of bypassing oil during acceleration and high speeds.

Not really true. Read some of @ZeeOSix’s helpful, fact-based posts that show this “requirement” likely only applies to Subaru OEM filters. If this were an issue, there would be class action lawsuits and millions of Subarus on the side of the road with failed engines.

I’ve personally driven over half a million miles in Subarus without using an OEM filter or with 23psi bypass ratings without a single issue.

You may want to take a look at my recent UOA on my ‘19 Ascent, that even with a bunch of fuel and silicon in the sample, the Fram Endurance filtered well enough that there was 0.1% soot and very, very low wear rate. If the filter was bypassing as frequently as the alarmists claim, there’s no way things would have looked this good.

 

[Nuclear_42]

I was trying to see if you did a UOA on the M1.

https://bobistheoilguy.com/forums/t...ck-2-5l-mobil-1-afe-0w-30-2-800-miles.385988/