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I know there’s been a lot of posts on using Shell Rotella T6 and using their new formula. I couldn’t find a solid answer so I contacted shell and was told the following:

“Rotella T6 5W-40 does not meet the performance requirements for API SN and is not suitable for your application - Subaru requires an API SN/ILSAC GF-5 oil for your engine, which Rotella Multi Vehicle 5W-30 is not rated for either. We would recommend using Pennzoil Platinum 5W-30 or Rotella Gas Truck 5W-30 instead”

I just wanted to see if anyone had any comments on this. I will be using Motul X-clean EFE 5W-30 instead of T6 for my ‘13 STI
 

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stop reading all that nonsense, Rotella T6 has been proved to be a good oil for years, i personally ran it on my previous stage 2 sti, and i drove it hard.
 

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Shell is telling you that because the default oil for an EJ257, per Subaru, is a GF5 RC 5w-30.

They cannot tell you to run 5w-40, because that would likely lead them to a lawsuit. so they are CTA.

As Russell said, use the 5w-40...and since you're car is a 2013 you probably dont have a warranty anymore anyway so no reason to use 5w30
 

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Discussion Starter #4
So even after the formula change it’s still good to use the new T6? Thanks a lot for both of your inputs!
 

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I wouldnt look to far into this honestly. 5w-40 T6 is fine for our cars and has been proven throughout the years. There is no number 1 oil or anything like that, its all preference. Its oil, just change it often and you will be fine.
 

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Over the last 150000+ miles the worst my stock 2008 sti ran was on the one round of T6 I ran. It was clunky and the gas mileage went to pot. That includes being worst than the first 25k miles where I ran the dealers dino. The last 100+k miles have been mostly castrol edge without consumption or other issues. So while I understand why guys with modified engines would use a thicker oil...i cant see anyone running stock would.
 

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Over the last 150000+ miles the worst my stock 2008 sti ran was on the one round of T6 I ran. It was clunky and the gas mileage went to pot. That includes being worst than the first 25k miles where I ran the dealers dino. The last 100+k miles have been mostly castrol edge without consumption or other issues. So while I understand why guys with modified engines would use a thicker oil...i cant see anyone running stock would.

How did runing 5w-40 over 5w-30 lead to car being "clunky" and bad gas mileage? :confused:
 

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How did runing 5w-40 over 5w-30 lead to car being "clunky" and bad gas mileage? :confused:


It’s the brand change, not the viscosity grade at warmed temps that’s the key to his message. I’ve noticed a difference between brands too all while using the same multi-grade viscosity.

Castrol Edge and Motul are the two that have had my engine running smoother than other alternatives.
 

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It’s the brand change, not the viscosity grade at warmed temps that’s the key to his message. I’ve noticed a difference between brands too all while using the same multi-grade viscosity.

Castrol Edge and Motul are the two that have had my engine running smoother than other alternatives.

If anything, i found that going to a 5w-40 "smoothed" the engine out a bit. I can see maybe reducing viscosity leading to a slight improvement of fuel economy but not much. I cant really see increasing viscosity to a 40 over 30 leading to "bad" gas mileage. Ive used Rotella T6 since my first oil change at 1K, done 3K OCI and havent looked back. Either way i dont want to get into another one of these oil wars. Im not a fluid engineer or anything like that.



I attribute my poor gas mileage to ID1000's :naughty:
 

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holds up better to the heat and thereby doesn't break down as fast...i have been running 5w30 with 1qt 15w40 and my tests came back saying viscosity was at 10w30 after ~4500 miles on it...all non-synthetic oil too
 

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If anything, i found that going to a 5w-40 "smoothed" the engine out a bit. I can see maybe reducing viscosity leading to a slight improvement of fuel economy but not much. I cant really see increasing viscosity to a 40 over 30 leading to "bad" gas mileage. Ive used Rotella T6 since my first oil change at 1K, done 3K OCI and havent looked back. Either way i dont want to get into another one of these oil wars. Im not a fluid engineer or anything like that.



I attribute my poor gas mileage to ID1000's :naughty:


It’s definitely subjective. I notice it a lot more in the winter.

But ya, gas mileage wouldn’t change that much. My ID1000s and my need to hear my Corsa exhaust at every acceleration is the cause for my bad fuel mileage.

I use Castrol Edge 0W40 in the winter and Motul 10W40 in the summer. Best combo I’ve found so far.
 

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my wear metals increased in 1 run of RT6 on my OEM engine compared to Pennzoil plat. 5w-30

not saying its a bad oil, but I think my clearances were too tight for the 40w.
 
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