Synthetic Diesel Oil...

dellman · Dec 26, 2002

Shell Rotella SB is a very good oil for a Group III oil Oils are classified as Group I, II, II+, III, IV and V. Group I, II and II+ are dino oils. Rotella T, Delo 400, Delvac 1300S ect. fall in these groups. Next we have group III which is a Hydrocracked dino oil. Castrol synthetic, Shell Rotella SB and alot of others fall in this category. While not being full synthetic, they are good oils, but overpriced for a dino oil.
Group IV and V are true FULL Synthetic oils, Delvac I, Mobil I, most all Amsoil, Red Line, and some smaller brands.

Mobil Oil Company sued Castrol for reducing their Full Syntheitc PAO based oil to Group III dino oil. This was taken to the advertising board of the BBB and it was ruled that they could call their oil Synthetic. So now everyone jumped on the band wagon. $3-$4+ for a dino grp. III oil is a high price to pay for this oil when full PAO synthetics are available at not much more.

In my diesels I use Delvac 1300S in one and Schaeffer's 15W40 7000 Series semi-syn in the other. Both are trucks. I will be changing the other to Schaeffer's at the next oil change.

neilw · Dec 26, 2002

dellman

I also use Schaeffer's 7000 series 15w-40. I think its the best $3.00 a quart oil anywhere.

Check out www.bobistheoilguy.com. Lots of oil talk, but for tractor talk you've got to be here.

OkieG · Dec 26, 2002

Thanks for the lesson on oil groups. Do oils for gas engines also fall into these groups? Do the additives that distinguish a diesel oil from a gas oil change which group an oil is in? Are the "full synthetics" recommended for both gas and diesel or would you buy one synthetic for gas and another for diesel?

OkieG

dellman · Dec 27, 2002

All oils gas and diesel fall in the 5 groups. The groups are base oils only, and the additive package is what determines the use of that oil. So the base stock of a gas oil can be a group I and the exact same base can be used in diesel oil. Synthetics can be used in gas or diesel depending on the API rating. Example Delvac 1300S that I have is rated API Service CH,CG-4,CF-4,CF,SL,SJ.

The C stands for COMMERCIAL and the S stands for SERVICE. This is the API use of those letters. So using the above rating for the Delvac we can see it is suitable for both diesel and gas engines. CH/SL, I always look for the highest rating on both C and H. This oil was purchased earlier this year, so now it would also include the CI rating. I purchased it prior to October 02, when the CI was first allowed to be labeled. Alot of oils were already API CI compliant but could not be labeled as such until 10/02. Delvac is an example. The new CI Delvac 1300S is almost black out of the bottle, but a very good oil.

Diesel rated oil can be used in an auto if it is so rated. The case of the Delvac 1300S is CH/SL. However this may not be the best choice in an auto. The Delvac I which is Full Synthetic PAO would be a better choice and is 5W40.

Another Synthetic oil choice for diesel and gas engines are Amsoil. The 5W30 HDD is my recommendation if you use Amsoil or the 15W40 Marine if you live further South. I am speaking of year around use.

I would not use Mobil I Super Syn in a diesel engine, unless you only require a SL/CF oil. The CF rating is so old, I am surprised it is still on the bottle. My rule of thumb when selecting a diesel oil is if the C rating is listed first then the S rating second, I would use it. Such as CI/SL. Mobil I is tops in an auto engine, but I personally wouldn't use it in a diesel as I stated it is API rated SL/CF. The S rating is listed first as this is an oil for primary auto use. It is best to check the owners manual for your requirements for both weight and API ratings.

Some of the non-API certified oil are excellent in diesels, John Deere 0W40 and 15W40 depending on your temps, Amsoil 5W30 HDD and 15W40 Marine. These are just examples.

I hope this is clearer than my previous post.

OkieG · Dec 27, 2002

Your input is very helpful. Does C = diesel and S = gasoline?

Your posts inspired me to do a web search on API ratings. I found a site that indicated that the second letter in the rating (ie the "I" in CI) is a measure of quality within the C or S categories, with A being the lowest quality and each successive alphabetical letter representing an increase in quality. So, SA oil would be the lowest rated oil. SB would be an improvement, and SC would be even better, and so on until you reached the highest rated oil in the S category (SL?). Same thing for the C categoy. CI is higher rated than CH and both are better than CG.

My interpretation is probably a bit simplistic. But, am I kind of catching on?

The website info didn't get into gas vs diesel, only that C (commercial) was intended for harder use than S (service) grade oils. From the Delvac 1300S API ratings am I to assume that not all CH rated oil is also CF or CG rated?..and not all SL rated oil is also SJ rated?

If an oil can have several C and/or S ratings, the second letter must indicate a special use (?), beyond being a general indicator of quality within the C or S categories. Is that right?

Sorry to bombard you with so many questions. Until recently I didn't know enough to even look at the API ratings, and bought oil based only on SAE. Thanks again.

OkieG

Bird · Dec 27, 2002

I haven't researched it, so I assume you guys have and the C=Commercial and S=Service, but I've always found it easier to remember that "C" is for Compression Combustion (diesel) and "S" is for Spark Ignited (gasoline) engines.

OkieG · Dec 27, 2002

Neil,

The website you recommended is something else! Here is a link to a post and responses somewhat related to our topic. Those guys really get on one another. No tolerance for mistakes.

Anyway, interesting and informative reading.

OkieG

OkieG · Dec 27, 2002

"C" is for Compression Combustion (diesel) and "S" is for Spark Ignited (gasoline) engines.

Good way to remember.

OkieG

JohnMiller3 · Dec 27, 2002

...Wonderful! Noticeably better...

Hi George,

Well, the lowest temps in my area has only been down to about 8 degrees, but winter just started about a week ago... however my JD starts as easy now (@ 8 degrees) as it does all year long... /w3tcompact/icons/grin.gif

But, I can't tell you if it's that "synthetic benefit" /w3tcompact/icons/eyes.gif or just plain "5w"... /w3tcompact/icons/blush.gif... never-the-less... I'm a happy camper and the initial results are telling me this is the way to go for winter usage... /w3tcompact/icons/smile.gif

Shell Rotella has a proven track record, being fully synthetic, extremely reasonable cost of a hair over $ 3. qt., and now @ 5w for truly winter temps... this is a lot of value and my JD is smiling out in the cold... /w3tcompact/icons/smile.gif

dellman · Dec 27, 2002

OkieG,

I am glad that you went to the API site. Alot of good info there and you are on the right track on the info.

An interesting way to find out what type oil you are using is go to the Company site and look at the MSDS. An example is Shell Synthetic is listed at 65-74.99% Hydrotreated Petroleum Slack Wax and 10-19.99% Hydrotreated Heaavy Paraffinic. So the Shell Synthetic is an excellent Group III dino oil with a pour point of -40C. But Delo 400 15W40 dino oil has a pour point of -39C at half the price of the Shell Syn.

Another interesting oil is the CAT 5W40 which is a True Synthetic and has a pour point of -54C (-65F). This oil is made by Mobil and looks close to a rebadged Mobil Delvac I.