Diesel Engine Oil

First time changing the oil on my new to me J/D 5203. Dealer
recommends 15W - 40W. What brands would you run if not
J/D, first diesel for me.

Rotella

Same 15/40?

Don't know if it would be a 15W-40 or a 10W-40 but either will be just fine. I run a 10W-40 Rotella in my IH584

I've always used the Walmart brand of diesel rated oil.

John Deere 15w 40 only.

Cenex is what i used in my ag engines

Your manual will tell you what API service categories are suitable for your engine. Any oil that is labeled to meet these requirements and is the proper viscosity will be fine. I personally use Shell Rotella in my stuff but I doubt it is really any better than anything else out there. For me it's more a matter of always using the same oil and the fact that Rotella is readily available.

Mobile Delvac is good to, and they have some killer rebates.

Mobil Delvac

Delvac, rotella t, delo, tractor supply, walmart, deere brand, something that meets the requirements.
Royal purple, Amsoil......

why ??????

1456;1256;826;706;400;M;SM........Pickup;lawnmower;4 wheeler........ALL use Fleet 15/40 from TSC.Used to use NAPA oil,too. Have for years with no issues.One oil for all,"keep it simple,stupid"(KISS systemLOL),no confusion!

Typically, a 10W-40 is a gasoline rated engine oil. A diesel engine oil will be a 15W-40. I've used Rotella in EVERYTHING, gas, diesel, lawn mowers, everything but the wife's car that need 5W-20. Rotella is available just about everywhere. Even grocery stores will have quart bottles and maybe gallons on the shelf.
Mobil Delvac is a great oil too. Every OEM manufacturer I've bought parts for used a Mobil oil as factory fill and recommended it for use. Delo is also good, Valvoline also. Buy and use what you can get easily in the future, I'm not one to change oil brands on vehicles. Like my 1996 F-250 with 7.3L PSD, 300,000 miles and something like 115 oil changes with Rotella, Put 14 quarts in, drain 13 quarts out 3000 miles later. Been like that since first oil change.

I use filters made or supplied by the engine mfg. The oil, whatever major brand that is readily available. I drove from Brooklyn, Michigan to Chicago, Ill. in a brand new Mustang GT that was close to a quart low on oil, bet I stopped at 20-30 gas stations & truck stops looking for a quart of 10W-40 Valvoline, could have bought several semi-trailer loads of Pennzoil, but not a single quart of Valvoline. Got home at 2 AM, went to the shop as soon as I shut the car off, got three quarts, put one in the engine and two in the back seat storage compartments. Had a similar situation several years before, oil pan on the 903 Cummins in my semi-tractor started leaking about 400 miles from home, steel oil pan rusting from water held against it by noise insulation. Engine would normally use about a quart of oil per 1000-1500 miles, I didn't carry any oil. I bought a case of quarts to get home.

As for brand, that's your choice. Name brand oils cost more, off brand are the same oil with a different label. You just don't know what brand unless you have some inside information as to what they use.

The owners manual will have a viscosity/temperature chart. Go by that information over what someone at the dealership tells you. What is in "writing" will always over ride what someone supposedly "said" should there be a warranty issue.

As for the proper oil, the manual will have an "API" rating. That's in the circle on the oil container. Look for something like "CK-4". That's the latest available technology oil.

Looking at the rating:

The first letter, S = spark ignition, C = compression ignition. Obviously you want C for compression ignition (diesel) engine.
There is also a new F rated oil. This is for diesel engines with a particulate filter for green house gas reduction.

The second letter indicates the "technology level" of the oil. K is currently the latest technology. The ratings are in alphabetical order, the higher the letter, the the higher the rating. If by chance an older engine called for a G, H, I or J rated oil, K will work, you just don't want to go the other way and put a lower rated oil in a higher rated application. In reality, anything you buy off the shelf will most likely be the latest rating. Only if you were to find some really old stock, or something that had been in the barn for years would you get the wrong grade. Still worth looking though.

The last number indicates for the type engine, 2 or 4 stroke.
Latest Oil Ratings

Thanks for all of the advise. J/D 15W-40W is $7.75 a gusty so now I?ll do some price comparisons. Thanks again.

Good grief another “ what is the best oil question”.

I use Walmart and TSC oil. It's all the same to me so I buy the cheapest price stuff I can get. Haven't had an oil related failure yet so it must be working.