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Discussion Starter · #1 ·
Please post your UOAs here.

This is my first UOA with the factory fill oil at 6-month interval. I didn't drive much hence the low mileage (just over 1800 miles). Ignore the high Silicon level for now because it's always high in first UOA due to sealers/gasket materials. Fuel dilution is super high just as I suspected. Oil on the dipstick always reeks gas, even right after the new oil was put in. I guess this is the nature of these Subaru DIT engines. I've been reading a WRX UOA thread (started since 2014) over at NASIOC forum and the FA20DIT engines have been doing the same thing. TBN and wear metal levels are still good so I'm not overly concerned though.
 

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This is cool - thanks for posting and may confirm the issue folks are having with rising oil levels. I also ordered a kit from Blackstone as I plan to do the first oil change soon. Ill post results back too.
 

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Discussion Starter · #3 ·
If you are interested in fuel dilution, use a different lab other than Black Stone. They only estimate instead of using Gas Chromatography to actually test for it so it's way off.
 

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Discussion Starter · #4 ·
VOAs for TGMO and PP 0W20

I've just sent these new oil samples in for analysis to use as baseline for (my) future reference. I'm currently running TGMO 0W20. Will have its UOA in October. It looks like the VOAs for both of these oils posted at BITOG and other websites are outdated because they both have changes to their formulations.

I hope someone on here find these useful. Seems there's no interest in UOAs/VOAs on here at all.
 

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Discussion Starter · #5 ·
UOA of TGMO 0W20 at 1306km (811 miles)

Being curious of the fuel dilution, I took a used oil sample early (only about 800mi). Sample taken using a sampling pump immediately after a 400+ km (~250mi) highway round trip at full operating temp so oil still hot. Fuel dilution is a little lower than last time but still very high (3.9%).

I put in exactly 5.0 L of oil on the last oil change so I can calculate exactly how much gas is in there at the sampling time (assuming no oil consumption, which I'm sure is not present):

5000 mL x 3.9% = 195 mL

That's almost half a water bottle worth of gas in the sump. Last oil drain was >5% FD so it was even worse.

[email protected] went from 8.4 cSt (per VOA on the blue NL line) to 6.9 cSt (sample 2 line) in a measly 800 miles!

Hopefully Subaru engineers knew what they were doing when they designed an engine with such high Fuel Dilution adding thinness to the already thin 0W20 recommended oil. I'm a little worried for the longevity of the engine now.
 

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Im curious to know if SOJ, assuming they designed the engine, account for the fuel dilution when considering the use of 0w20.

Thanks for the analysis and evaluation.
 

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I brought my 19 ascent into the shop with about 600 miles on it after I looked at dip stick that was about 1/2 inch over full mark. They changed oil, level on stick "spot on" full, said keep an eye on it. Less than 200 miles later, another 1/2" over full mark. Took back to shop. Gave me a loaner Ascent. Did tests with bore scope to see if fuel was leaking from injectors into cylinders which it was "not". Fuel pressure pump was losing pressure after sitting over night. Waited for Dealership to see what SOA wanted them to do next. Less than 800 miles on my new car. I called SOA and Rep. said if they can't fix, they would replace vehicle with "Good Will" program to restore my confidence in Subaru "if needed". Friday, 5/17, Dealership called me and said SOA authorized them to replace "fuel pump" in engine. Dealership ordered new pump and will replace this week. I love this car and many reasons I bought it which also satisfies my uses also rides and handles great but starting to regret buying it which I told SOA and Dealership. Working with Dealership has been "great", as I also bought an 18 Outback from them about a year ago also. Dealership people have been super to work with in the past and also now. Their hands are tied on doing anything to fix my car as they have to do what SOA tells them to test and fix the car. I suggested send oil to test for fuel which they have not done, I suspect SOA has not authorized to do so. Being patient here to get my car fixed is all I can do at this point. Hope the pump replacement fixes the problem and if not will have to pursue the Good Will program for a new one. Dealership told me they did not have rising oil level issues with any other Ascents they have sold. Luck of the draw for me, I guess and hope I'm getting the straight scoop on that story.


If fuel or any other oils mixing in with crankcase oil causing rising oil levels, this may be very big issue with Subaru and lead to class action. Sure hope not and keeping fingers crossed as I went through class action with V.W. Jetta diesel for different issue/emissions, couple years ago which took forever.
 

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There is no acceptable level of gasoline in an engine crankcase, other than trace amounts of a % or 2. Any amounts large enough to smell and raise the oil level are going to be fatal to the engine. Synthetic oil can cover a lot of ills, but gasoline will cause metal - metal contact resulting in nothing good. the diesel in my tractor is noted for it's fuel pump leaking and contaminating the crankcase with diesel, which mixes right into the oil, and you can't smell it over the oil smell. But you can see the oil level rise. If these engines are being sprayed with enough fuel to get past the pistons and raise the level of the crankcase, that's a major screw-up and should be enough to trigger an emissions indicator.
Great, something else to watch for.
 

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There is no acceptable level of gasoline in an engine crankcase, other than trace amounts of a % or 2. Any amounts large enough to smell and raise the oil level are going to be fatal to the engine. Synthetic oil can cover a lot of ills, but gasoline will cause metal - metal contact resulting in nothing good. the diesel in my tractor is noted for it's fuel pump leaking and contaminating the crankcase with diesel, which mixes right into the oil, and you can't smell it over the oil smell. But you can see the oil level rise. If these engines are being sprayed with enough fuel to get past the pistons and raise the level of the crankcase, that's a major screw-up and should be enough to trigger an emissions indicator.
Great, something else to watch for.
It's not a normal occurrence. Nor is it happening a lot, if that helps. I suspect they will figure out why a few cars are doing it.

 

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Greetings,
If I've a problem with gas getting into the oil, would the level continue to increase over time? My level is a little high, but it hasn't gotten higher since I first checked it about 4 months ago.
 

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Greetings,
If I've a problem with gas getting into the oil, would the level continue to increase over time? My level is a little high, but it hasn't gotten higher since I first checked it about 4 months ago.
Yes. It would keep rising.
 

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Here is my UOA from an ascent with 18k miles. Oil was used for 6k miles and I've always smelled a bit of gasoline when restarting after driving for a while. I had a high reading on the dipstick and also thought the viscosity of the 0w20 looked really thin when draining for an oil change. So I was worried about fuel dilution but it looks like it isn't significant. I know Blackstone only estimates dilution via flash point but even with that error it doesn't look like dilution is a problem.

Note that I mislabeled this as Mobil 1 0w20 but the dealer actually did this change so I'm guessing they used idemitsu. Next UoA will be for M1 which is what I use when I change the oil.

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This looks great -- was the oil the standard M1 AFE 0W-20? Or one of the longer-drain or high mileage ones?
Actually as I think through it I realized that the dealer did this change so it is whatever they used (Idemitsu?). I used M1 AFE 0w20 at 3000 miles, dealer did 6k and 12k, and I just did the one at 18k. Sorry for the mis-label. I will send the current oil off for analysis when it hits 6k miles and will post that.
 

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Actually as I think through it I realized that the dealer did this change so it is whatever they used (Idemitsu?). I used M1 AFE 0w20 at 3000 miles, dealer did 6k and 12k, and I just did the one at 18k. Sorry for the mis-label. I will send the current oil off for analysis when it hits 6k miles and will post that.
OK, here is the latest using Mobil1 0w-20. I was a little late on the change but the oil came out looking good.

11762
 

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Oil sampled at 1243 miles.

First oil change was at 594 miles because of rising oil level, suspected fuel contamination. No oil analysis done at 594. They just wanted to establish a baseline.

Both dealers I frequent use Mobil 1 0W20 for oil changes. Or at least the window reminder stickers say so.

Note: oil contaminated with almost 5% fuel after 600 miles.


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<<<<<
Who has two thumbs and had a fuel dilution problem but doesn’t have one any more after switching to 5w30 oil because the factory recommendation was based on fuel economy and not for the betterment of the engine?
 

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^^^^^
Who has two thumbs and had a fuel dilution problem but doesn’t have one any more after switching to 5w30 oil because the factory recommendation was based on fuel economy and not for the betterment of the engine?
Do you have the tests? Can you share?
 

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Do you have the tests? Can you share?
Just basing it on my own observations. I noticed the gas smell when checking the factory fill oil, the oil was above the full mark by a bit. I'm very proactive in changing oil on a new vehicle because of high initial wear metals and silicon that gets in the oil. So, after changing the factory fill, I used some 0w20 Super Tech (since I was going to change again soon to rid the engine of wear metals), and noticed the gas smell again, swear I noticed it inside the vehicle a time or two as well.

After that I switched to Castrol Edge 5w30. Zero rise in oil levels and no more gas smell. I just changed the oil today (didn't notice gas smell)and went with Quaker State full syn 5w30 because of it's lower calcium in order to deter LSPI events form happening. I had no issue with the Castrol Edge, just wanted to try something different to see if things feel/sound better.

I change the oil every 2500 miles because it's a severe use vehicle (lots of short trips, some boat towing), and it's easy to remember the intervals that way. I change the filter every 5k because the syn media filters I use are made for 10k+ miles, so no point in doing it every oil change. I do the same in my work truck, oil every 3,333 miles and filter every 10k, air filters at 10k on both vehicles also. Frequent oil changes are cheap insurance to ensure your vehicle has good oil in it. A turbo engine that does a lot of short trips is especially worthy of frequent changes, especially with already water-thin oil (if you're using 0w20).
 
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