Best 5w-30 syn for Subaru WRX 2.5L turbo EJ 255

[vtdave]

Some of the best UOAs for the Subaru 2.5L (EJ 255) turbo engine are found in Rotella T6 5w-40 (SM) and GC 0w-30 (SL). There is almost a cult following.

But now, effective mid-2011, Subaru states that a 5w-30 SM+/GF4+ energy conserving or resource conserving synthetic oil is the REQUIRED oil. There is no wiggle room. So, for warranty purposes it's goodbye RT6 and GC, even though the EJ 255 motor hasn't changed since 2006 and those oils have an excellent track record in this application.

Here's the question: which oil meets the required specifications, but most closely mirrors the positive attributes of RT6/GC? It has been said that the EJ 255 is hard on oil, shears it quickly, and suffers from the occasional spun bearing when the oil gets too thin under demanding (hot) conditions. Accepting these premises as true for sake of argument, which 5w-30 SM+ EC synthetic is optimal?

Thanks,
Dave

PS - First post!
PPS - I know this general topic has been discussed many times over on NASIOC, but no one has posed this exact question before.

 

[Solo2driver]

I would use the Subaru OEM Synthetic if you are truly concerned about warranty issues. I ran Pennzoil Ultra 5w-40 Euro in my '11 WRX, traded it in at 18K mi. My '12 WRX is on it's second round of Royal Purple HPS 5w-30. SOA has replaced my '12 Impreza 2.0i under warranty already (Lemon Law: airbag issues), I wouldn't hesitate to go 10 rounds with them over an oil issue.

Keep synthetic oil in it to prevent coking in the turbo (the main reason they require it), change at your choice of 3750mi or 7500mi depending on which documents you choose to believe. I change it at the Severe interval, cheap insurance.

PS-- mine is heavily autocrossed, ProSolo events, and will likely see a NASA Time Trial event or three before the end of the year. Srs bsns.

 

[Indydriver]

Welcome to BITOG, Dave.

I had similar questions about my Mazdaspeed3 which also specs 5W-30. I did several short OCIs with PYB to make sure I got all the break in goodies out of there and then went with PP synthetic at 18,000 miles based on many good UOAs both here and on the fanboy sites. I believe very strongly that if you stick with one of the majors that meet your manufacturer's specifications that you simply can't go wrong. One slight edge brought by Pennzoil and Mobil1 with their 5W-30s is that they also meet Honda's HTO-06 spec for turbocharged engines. To my knowledge, this is the only turbo-specific certification out there. So, it gives another little extra comfort level with these flagship products from the two leading oil companies in the world. So, start there while you learn more about oils and what your car likes. Keep your intervals conservative and do a few UOAs to learn more about the condition of your specific engine and its oil. You will soon figure out the sweet spot.

 

[oggb]

Use any synthetic 5w-30 and 5,000 mile OCIs max until you're out of the 5yr/60k powertrain warranty. If something breaks under warranty related the powertrain you're likely to have a fight on your hands anyhow.

Then switch to whatever you want, preferably Rotella T6 or Mobil 1 0w-40.

 

[bluesubie]

Actually the manual says 5W-30 API SM or SN. It also says "5W-40 conventional" can be used for replenishment and there is no such oil! Max Life Full Synthetic has a 5W-30 API SM oil that meets European ACEA A3 (like GC). Motul x-clean C3 5w-30 is also SM/ACEA A3.

I wouldn't run a Resource Conserving oil in a Subaru turbo even if it were free. Although I am curious about the new GF5 oils because they're producing some good uoa's. You won't find more than 3 or 4 uoa's on them though (here and nasioc) because most people that do uoa's are afraid to run them. There's just not much trending data. Using google, you might be able to find the few posted here.

There are people running GC in 2012's that was changed by a dealer. I wouldn't be afraid to run a non API 5W-30 like Red Line or the Royal Purple HPS that Solo2 mentioned above. Your exact question gets posted here every other week.

YMMV!

-Dennis

 

[vtdave]

Thanks everyone.