Shell Rotella

[60eldo]

  Can we use shell rotella 15 40 desil in our cars. I ask cause I used to use it and I see that now its only for deisal.

[TJ Hopland]

Interesting, I will have to look at a bottle next time I am in a store.  It actually says not for gas engines or only for diesel now?   How about the API label?  They used to have both a C and S rating, S is the gas rating.  I could see them not meeting newer S ratings but you would think they would still meet older ones. 

Personally I would still use it.  Several years ago I switched to a store brand that I buy in 5 gallon pails and the last one of those I bought still had both C and S rating on it but I will have to check that too next time I'm in that store. 

[Daryl Chesterman]

Shell Rotella T4 is still rated for gasoline engines.  My only problem with using oil with that high of viscosity is the slow cranking in cold weather—hard on the starter and it doesn't provide immediate upper end lubrication.  If the car is parked in storage during cold weather, then it is no problem.  See the Shell Technical Data Sheet:

     https://www.shell-livedocs.com/data/published/en-US/718f5851-4880-43db-95a1-bbf45aeaca8f.pdf

Daryl Chesterman

[David Greenburg]

I have used T4 with no issues, but I don't have to deal with cold weather. It is one of most affordable high ZDDP oils.

[James Landi]

Oil choice and viscosity on our old engines is an interesting topic that's been extensively covered, yet the question is full of ambiguity. For those of us who have installed oil pressure gauges to supplement idiot lights, the "nervous Nellys" among us begin to pull out what remains of our hair when we observe our pressure gauges dropping to 7 psi at idle (with the idiot light occasionally blinking) in hot weather. A good quality, multi-grade detergent oil such as SHell's Rotella is a good choice, especially for summer driving. On some of the original "Owner's Manuals" for certain model years, most notably 4100 engines in the early 80's, Cadillac recommended single viscosity 30 weight detergent oil for summer driving.  I've owned more than a dozen old twin engine GM Marinized gas and diesel boat engines (2 stroke Detroits,GM 454's and 502's) and GM recommends straight 30 or 40 high detergent oil.  Of course, boat engines never coast, and in order to obtain any speed, they run at 90 % of their capacity, so I suspect the final answer is "it all depends"--- on how you drive, how long your longest trips are, as well as, most importantly, the degree to which your cooling system is either totally clean or substantially clogged. From my nearly 60 years of tinkering with old Cadillacs, I'd recommend the need to concentrate on all aspects and components of one's cooling system, and use a good quality multi-grade, and never, ever push that old accelerator pedal to the floor.    Happy day, James

[TJ Hopland]

I think the actual question is has something changed recently in their formula or rating system or is it just some sort of marketing change?  Or has Jon perhaps run into some counterfeit product?

[Artistic Precision]

Im running it in my car. But I have a Pontiac 350 in there. The guy at the parts store was a pontiac guy and thats what he recommended for it.

[TJ Hopland]

It does look like Shell made some changes in the T6 line in last year or three.  The standard 'Shell Rotella T6 Full Synthetic' no longer carries the S rating for gas engines however they now have a newish product in the lineup called 'Shell Rotella T6 Multi-Vehicle' that does. 

I'm not really concerned about the drop in the S rating.  I'm using the diesel oils in stuff older than 2000 and most pre cat or small engines that don't have cats either.  It seems its the cats and other emissions equipment and requirements that are the changes in the formulas for both gas and diesel engines. 

I buy Dexos rated oil for my 2013 Chev truck and the VWAG stuff for my 2015 TDI. Everything else gets 5w-40 diesel oil in my fleet or that comes into 'my shop'.  Been doing it that way for about 15 years now and its worked well for me and reduced what I have to stock which was one of the main reasons.  One 5 gallon pail on the floor replaced a whole shelf of various oils.  If I didn't have any diesels in the fleet I may not have gone with a diesel oil but for old stuff in a climate that gets hot and cold 5w-40 is a great fit and that most commonly comes as a diesel oil.       

The MV carries a SN gas rating which came out in 2020. SP looks to be the current rating which came out in May of 2020 presumably for 2021 models?  My guess is what ever that SP requirement was just could not be done with the current CK-4 diesel rating which came out in 2017 so to keep a product that can meet fairly current specs for both they had to create this new product.  I have not noticed it in stores I shop at but the label isn't that different so not knowing it existed it I may have seen it on shelves and not noticed.

Just for reference here is the list of API S ratings.  SA was 1930. SB was 1951. SC was 67 then there are roughly 10 year jumps that got us to SG in 1993.  After that there are several that just lasted a couple years. 
https://www.api.org/products-and-services/engine-oil/eolcs-categories-and-classifications/oil-categories#tab-gasoline