i personally use Shell GTL 5w-40 in my 08 Legacy, where i live is warm all year round. since subaru recommends either 5w-30 or 5w-40 for my model of subaru(EJ20 N/A) i use 5w-40. I have use 10w-40 in the engine once but changed it back to 5w-40 because the engine was burning oil. As for the using diesel oil, usually diesel and gas oils have different additives but this when out the window when oil manufactures started making one oil for newer gas and diesel vehicles like shell's GTL oil.
5w40 in Subaru?
- Thread starter Camprunner
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Originally Posted By: Camprunner
Today in WM I ran into a friend in the oil section and he was buying several quarts of Shell Rotella T synthetic 5w40 for his Subaru WRX I asked him doesn't your car recommend a 5 or 10w30? He said yes but he said many WRX guys like to run this?
Is this a common oil for Subaru WRX guys? Does the 4w40 show good UOA?
Yes, very common as others have said.
Do you know if the WRX is 2015 or earlier? The older WRX's with the EJ engine are more prone to bearing problems on thin oil. The STI still uses the older EJ engine and there have been several bearing failures even on late model, unmodified STI's for the past couple of years (possibly a manufacturing issue?).
The newer engine in the 2015 and later WRX has direct injection and many enthusiasts are running GF-5 and lower SAPS ACEA C3 oils in hopes of mitigating intake valve deposit issues. For the most part, these engines seem to be doing ok with high fuel dilution (2-5%) and thin oil. Note that Subaru Japan allows high SAPS 0W-30 and 5W-40 in these newer DI engines.
Here's a very good WRX specific thread where Doug Hillary talks a bit about the history of using HDEO's in petrol cars back before some of us were born.
He does state:
Quote:
Modern appropriately classified lubricants as recommended by the engine's Manufacturer have almost effectively negated their use in petrol engines today IMO.
I think RT6 in a WRX (and among other enthusiasts) became so popular because people wanted a robust oil and something cheap from Wal-Mart. Lately, M1 0W40 and Castrol 0W40 have become a bit more popular among WRX enthusiasts. Probably because they're now more readily available at Wal-Mart these days.
Today in WM I ran into a friend in the oil section and he was buying several quarts of Shell Rotella T synthetic 5w40 for his Subaru WRX I asked him doesn't your car recommend a 5 or 10w30? He said yes but he said many WRX guys like to run this?
Is this a common oil for Subaru WRX guys? Does the 4w40 show good UOA?
Yes, very common as others have said.
Do you know if the WRX is 2015 or earlier? The older WRX's with the EJ engine are more prone to bearing problems on thin oil. The STI still uses the older EJ engine and there have been several bearing failures even on late model, unmodified STI's for the past couple of years (possibly a manufacturing issue?).
The newer engine in the 2015 and later WRX has direct injection and many enthusiasts are running GF-5 and lower SAPS ACEA C3 oils in hopes of mitigating intake valve deposit issues. For the most part, these engines seem to be doing ok with high fuel dilution (2-5%) and thin oil. Note that Subaru Japan allows high SAPS 0W-30 and 5W-40 in these newer DI engines.
Here's a very good WRX specific thread where Doug Hillary talks a bit about the history of using HDEO's in petrol cars back before some of us were born.
He does state:
Quote:
Modern appropriately classified lubricants as recommended by the engine's Manufacturer have almost effectively negated their use in petrol engines today IMO.
I think RT6 in a WRX (and among other enthusiasts) became so popular because people wanted a robust oil and something cheap from Wal-Mart. Lately, M1 0W40 and Castrol 0W40 have become a bit more popular among WRX enthusiasts. Probably because they're now more readily available at Wal-Mart these days.
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Originally Posted By: CATERHAM
The specified 5W-30 is certainly heavy enough even for spirited street use.
Most of the problems I've heard about have been attributed to oil starvation and a heavier oil isn't going to help much under those conditions.
Depends upon what gets starved for oil. There is very specific and compelling evidence of turbo oil starvation in multiple engines. The turbo oil supply flow is purely a function of oil pressure at the tap point for the supply line. Accordingly, a higher kinematic viscosity is the way to assure sufficient pressure, and therefore flow, to the turbo.
I freely acknowledge and assert that HDEO vs. PCMO is a red herring.
The specified 5W-30 is certainly heavy enough even for spirited street use.
Most of the problems I've heard about have been attributed to oil starvation and a heavier oil isn't going to help much under those conditions.
Depends upon what gets starved for oil. There is very specific and compelling evidence of turbo oil starvation in multiple engines. The turbo oil supply flow is purely a function of oil pressure at the tap point for the supply line. Accordingly, a higher kinematic viscosity is the way to assure sufficient pressure, and therefore flow, to the turbo.
I freely acknowledge and assert that HDEO vs. PCMO is a red herring.
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