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Shell Rotella T6 5w-40 IS NOT SN RATED, it is not for use with catalytic converters.

I don't know why people get obsessed about using this specific oil in gasoline engines and continue to claim it is acceptable to use as if it were no different than anything else specified for gasoline engine usage.

I am tired of seeing these posts and having to address this, I am going to delete every post in this thread that has suggested the usage of this oil for reasons people continue to misunderstand.
That can't be accurate. Many diesel vehicles have catalytic converters and call for diesel oils including these diesel grades of Rotella T6.
 

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That can't be accurate. Many diesel vehicles have catalytic converters and call for diesel oils including these diesel grades of Rotella T6.
Like I mentioned previously, and it seems that this is either not being read or it is being ignored, that not all catalytic converters are the same. We are talking about gasoline engines and gasoline engine oil in THIS thread and it should follow that any reference to catalytic converters would relate to those used with gasoline engines and approved gasoline engine oils.
 

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I have read before of concerns with cat convs and the T6 5w-40. But I guess I was misremembering as I though it was excess zinc or zinc compound that was worrying?
 

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My biggest question towards anyone who would want to use a 40 weight version of Rotella T6 in a gasoline engine is why not just use another commonly available, similarly priced oil instead which has full approval for gasoline engine usage?

Here are a few examples I can think of that are all SN rated and carry several high end manufacturer approvals:

Valvoline Advanced Synthetic 0w40

Mobil 1 0w40

Castrol 0w40
Castrol 5w40
 

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I have read before of concerns with cat convs and the T6 5w-40. But I guess I was misremembering as I though it was excess zinc or zinc compound that was worrying?
It's the phosphorus that causes concerns with cat clogging. A side by side Blackstone comparison showed that the newer version has a tad less phosphorus, but Shell decided not to go for the gasoline engine spec anyway. Probably because they also came out with the RT6 5W-30 MultiVehicle as well.


@Kevin, when RT6 started gaining a following among WRX owners the oils that you mention were not that commonly available and/or reasonably priced. Even GC was hard to come by and was often out of stock when it was on sale. I think this is all part of the reason that RT6 because so popular. I remember reading about Mobil 1 0W-40 being available at Wal Mart long before I ever saw it pop up in Central NJ. Another reason for RT6 popularity is probably due to a lot of misinformation on forums that claimed ALL ZDDP was removed from oil during the switch to API SN (and probably API updates before that). I think it lost some popularity on nasioc when the FA20DIT came out and it was known that high SAPS oils contributed to intake valve deposits.

Here's some info from Doug Hillary at BITOG that talks about the history of HDEO's in performance cars:

I first experimented with HDEos in petrol engines in Europe in the early 1960s when working in Copenhagen for Caltex-Chevron in a Technical position

This was prompted by various experiences, excessive engine deposits in certain engine families, "poor" petrol engine lubricant standards and motivated by the results coming out of MB and Porsche. Porsche FF in the 1950s-1960s was a Shell HDEO

I've used HDEOs in petrol engine ever since - for nearly 50 years!

This was confirmed by extensive lubricants field testing for a number of Oil Companies over several decades

Modern appropriately classified lubricants as recommended by the engine's Manufacturer have almost effectively negated their use in petrol engines today IMO

My dealings and comparisons of HDEOs started in the early 1960s. I was always motivated by the MB and CAT lubricant specifications at a time when very few existed. I've always found that Shell and Delvac products produced the cleanest engines as the end result.
 

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It's the phosphorus that causes concerns with cat clogging. A side by side Blackstone comparison showed that the newer version has a tad less phosphorus, but Shell decided not to go for the gasoline engine spec anyway. Probably because they also came out with the RT6 5W-30 MultiVehicle as well.


@Kevin, when RT6 started gaining a following among WRX owners the oils that you mention were not that commonly available and/or reasonably priced. Even GC was hard to come by and was often out of stock when it was on sale. I think this is all part of the reason that RT6 because so popular. I remember reading about Mobil 1 0W-40 being available at Wal Mart long before I ever saw it pop up in Central NJ. Another reason for RT6 popularity is probably due to a lot of misinformation on forums that claimed ALL ZDDP was removed from oil during the switch to API SN (and probably API updates before that). I think it lost some popularity on nasioc when the FA20DIT came out and it was known that high SAPS oils contributed to intake valve deposits.

Here's some info from Doug Hillary at BITOG that talks about the history of HDEO's in performance cars:



Thank you for all that you have shared. From my perspective I have had so many question me with a mindset of, "why can't I use it" as if it should be just as acceptable to use as any other oil by default. Nevermind that is an HDEO rated primarily for diesel engine usage and its gasoline certification ended at model year 2009. I just don't get why so many people are so adamant about using it in the current day when there are so many more applicable oil choices out there and often can be had at a lower price.

And the fact that people want to argue in favor of using it in a vehicle that is not turbocharged and in a gasoline vehicle that is model 2010 or newer just boggles my mind. I had a 2006 turbo that I used RT6 5w-40 in from the first time I changed the oil until I got rid of it for a 2010 Outback. The stuff worked great and I have no qualms about anyone using it in an appropriate application. But it is these people who question using it in an application where it is unnecessary and/or unwarranted that pretty much want you to talk them into feeling like they are making a good decision by dumping it in their crankcase, I will never understand.
 

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Thank you for all that you have shared. From my perspective I have had so many question me with a mindset of, "why can't I use it" as if it should be just as acceptable to use as any other oil by default. Nevermind that is an HDEO rated primarily for diesel engine usage and its gasoline certification ended at model year 2009. I just don't get why so many people are so adamant about using it in the current day when there are so many more applicable oil choices out there and often can be had at a lower price.

And the fact that people want to argue in favor of using it in a vehicle that is not turbocharged and in a gasoline vehicle that is model 2010 or newer just boggles my mind. I had a 2006 turbo that I used RT6 5w-40 in from the first time I changed the oil until I got rid of it for a 2010 Outback. The stuff worked great and I have no qualms about anyone using it in an appropriate application. But it is these people who question using it in an application where it is unnecessary and/or unwarranted that pretty much want you to talk them into feeling like they are making a good decision by dumping it in their crankcase, I will never understand.
Well, I admit to being lazy and not shopping for an alternative. But, due to your post, I'm going to investigate the Castrol oil I think.
 

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Well, I admit to being lazy and not shopping for an alternative. But, due to your post, I'm going to investigate the Castrol oil I think.
I can't stop anyone from doing anything, if you want to put 40 weight RT6 in your gasser be my guest. I am going to strongly advise against it in many cases but ultimately I am just a guy that is trying to prevent the spread of bad information and potentially bad choices :)
 

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Shell Rotella T6 5w-40 IS NOT SN RATED, it is not for use with catalytic converters.

I don't know why people get obsessed about using this specific oil in gasoline engines and continue to claim it is acceptable to use as if it were no different than anything else specified for gasoline engine usage.

I am tired of seeing these posts and having to address this, I am going to delete every post in this thread that has suggested the usage of this oil for reasons people continue to misunderstand.
 

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I can't fathom many reasons to use T6 in an OB when so many better oils are available.

SN is a spec that's 10 years old and is two steps behind the current one. D1G2 and A5/B5 too aren't available with T6 and it's a diesel engine that met an old gas standard.

You wouldn't walk into Dollar General and buy a 99 cent quart of an SJ rated oil and use it in your OB. You could but why? Why not?

Seems that modernly, people use T6 in their OB or other cars to be edgy, unique or just feeling like a special flower. There's no current reason to use it. Plain vanilla M1 shames it.
 

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I believe this thread is primarily about RT6 5W-40.

But Rotella T6 MV 5W-30 is SN+ rated and this was confirmed by Shell. Despite it not being dexos rated, it’s probably still a good choice in a DIT, IMO, if you want a 5W-30 that will stay in grade because of the high HTHS.


 

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I believe this thread is primarily about RT6 5W-40.

But Rotella T6 MV 5W-30 is SN+ rated and this was confirmed by Shell. Despite it not being dexos rated, it’s probably still a good choice in a DIT, IMO, if you want a 5W-30 that will stay in grade because of the high HTHS.


Yes I have made multiple posts in this thread and otherwise about using Multi-Vehicle 5w30. I should probably amend the thread title to reflect the fact that the question at hand is about using SM rated RT6 5w40.
 

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if you read the link the oil is equally rated for gasoline and Diesel engines. Contrary to the claim of diesel only.

There is now a diesel only Rotella but that us only a recent development.
I think we agree :)

I have spoken about RT6 Multi Vehicle 5w30 multiple times in this thread and the fact that it is SN rated. Why so many people are not seeing it as an appropriate alternative to SM rated RT6 5w40 (that they are so adamant about using) I may never understand.
 
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