In general low Saps should Have less but how much I do not know. Give it all a try & test to see final results.
2021 WRX STi - Switched from OEM oil to Motul X-clean EFE 5w30 - 19,685 miles
- Thread starter JVILLA
- Start date
It doesn’t have anything to do with sulfur in the oil. “Sulfated ash” is a description of the analytical test where you react the metallic constituents with sulfuric acid.
edyvw
$50 site donor 2025
Only issue here is copper leaching.
Absolutely nonissue with oil! This is UOA not analysis of used engine.
Absolutely nonissue with oil! This is UOA not analysis of used engine.
I had a similar problem with my 16 wrx using motul xclean 5w40. kept going up. if it was leeching from the oil heat exchanger it would be high then taper off. i emailed my tuner (ron watson), he had a customer that had a similar experience. that guy switched to penzoil, still high. then switched to rotella t6 and it immediately went down. I switched to rotella t6 5w40 and mine went down immediately. viscosity is maintained higher for longer too. wear metals are staying low. not much else you can ask for. only problem is it comes in 4 quart jugs so no more one and done 5 liter jug oil change.
i'll have to find my latest oil analysis.
also cold starts were quieter (with stratified start off the fa20dit can be noisy due to timing chain rattle)
i went 3 oil changes and it was rising. shortened my interval. then switched to the shell and it immediately went down, and now good for a few oil changes. I know the oil geeks are going to have a field day with using a diesel oil though.
i'll have to find my latest oil analysis.
also cold starts were quieter (with stratified start off the fa20dit can be noisy due to timing chain rattle)
i went 3 oil changes and it was rising. shortened my interval. then switched to the shell and it immediately went down, and now good for a few oil changes. I know the oil geeks are going to have a field day with using a diesel oil though.
edyvw
$50 site donor 2025
For the lack of better world, T6 is not as good oil. It is good commercial diesel vehicle oil with huge sumps, but for these engines, it is not.
It is Group III, less "sophisticated" oil. Any oil that has such approvals as MB229.5, MB229.51/52, BMW LL01/04 etc. is of higher quality.
Reason for leaching is base stock and additive composition. It is common with oils such as Redline etc. that have a lot of Esters.
There is nothing wrong with EFE. Here are my UOA from Atlas. One with 5,182mls is EFE 5W30, one on the left, 5,000mls, is EFE 0W30:
clear as mud which one is which.
edyvw
$50 site donor 2025
For the 2.0DIT IAG actually recommends Motul X-Clean. They actually found issues with deposits in the early days of the 2.0 running high SAPS oils.
But for the OP's EJ they recommend Motul X-cess.
https://www.iagperformance.com/content/documents/Engine-After-Sale-Shipping-Doc.pdf
I don't really see the point of running reduced SAPS oils in an STI. Presume just to stick with 5W-30. I'd run Castrol Euro 5W-30 A3 over a reduced SAPS xW-30 though.
Exactly… I mentioned this. OP has an engine that was designed when API SL or even SJ was the only gig in town. That’s why I mentioned A3/B4 with its >3.5 HTHS requirement.
Running SN+ resource conserving of the shelf-stock oils in a hard-driven EJ257 is a guaranteed way to become an engine builder’s favorite customer IMO…
it is my understanding that leeching will start high when you change oils (or install new parts) and taper off. x-clean or x-cess is a moot point in this case. i'd try a different oil. i don't know that the sti has an actual oil cooler. the wrx has a heat exchanger which is basically a metal housing the oil filter sits on top of. if he's installed an aftermarket oil cooler then it could certainly account for the copper, but would definitely shorten OCI's and trend if not change brand immediately. in my case mine went up on the second oil change (even accounting for copper ppm per 1k miles and did not drop drastically with shorter oil change intervals) also the motul was shearing down below the desired range by the time i changed my oil (3k mile OCI's). I am now working on trying 5k mi OCI but at 3k the t6 maintained viscosity better. if the end results are lower levels of wear metals then what else do you need an oil to do. plenty if guys have not had that issue with motul. just mine and one other wrx tuned by ron (and the other guy tried penzoil with not luck either).
the only thing to do is shorten oci's and/or change oil brand. oil is cheap.
That is the sTI’s oil cooler. A copper water-to-oil heat exchanger. It will still be cooling the oil under hard use.
OP is doing 2k OCIs for what’s essentially daily driving. Copper from leeching is not a reason to condemn an oil. It doesn’t matter that oil is cheap, if he keeps playing round robin every oil change to a different brand he’s never going to be able to have any idea what is “normal” for his engine.
OP needs to pick an oil with sufficient HTHS for an EJ257, and run it at least 3 OCIs so he can discern if there’s copper “wear” or copper from the exchanger. Considering everything else looks good, it’s fairly doubtful even for an EJ that the copper is “wear”.
This Motul was run for 3 OCIs. Copper was down on the latest one. What about the silver, though?
I’ve never seen silver in my EJ UOAs. Maybe @Trav has some input?
