Oil & Fuel Oil Type for your Kubota........

[DieselPower]

Excellent post hill. Further goes to explain why you shouldn't assume that the same weight oil you dump into some huge Cummins is the appropriate thing for your Kubota. Again, I think this is really applies to when the engine is relatively new. Later down the road if you want to switch things up, I don't think it matters so much.

Actually if you check the owners manual of many of today's large truck engines like Cat and Cummins you will find 10W/30 as one of the suggested viscosity's. Even the new C7 Cat's manual states that in my area you can use a 10W/30 viscosity.

One reason many manufacturers are going to a lighter viscosity is fuel consumption. If you can cut down on internal resistance created by the lubricating oil then you can reduce fuel consumption. Thats why a large portion of the auto industry is going to 5W/20 and most recently even 0W/20 engine oils.

 

[rdam]

It's all about clearances. Smaller clearances means less space between metal parts, and oil viscosities are carefully chosen to minimize the time it takes to force oil into all of those spacings. I think it's safe to assume that if a manufacturer specifies a given oil viscosity for a particular engine it is doing so with careful consideration to all of the factors which dictate the full flow of lubrication to all of that engine's parts and we do well to follow their recommendations.

It does not work to decide that if it is diesel then such and such oil is right for it. There is no standard diesel oil.

That is the best explanation yet. I hope it's right. I am a big fan of synthetics, and use them exclusively in my air cooled motorcycles and Cub Cadet lawn tractor (Mobile 1). In my F-250 diesel (6.0), I am using Rotella 15W-40 and changing it every 4-5K miles. I tried Mobile 1 in the F-250 for 5000 miles and noticed no difference in performance, mileage, or engine noise. And while I know the synthetic is better, it is just a little too much money for 15 quarts of Mobil 1, compared to the relatively low cost of the Rotella T.

So, since I was using and usually had plenty of 15-40 Rotella on hand, I had planned to use it in the Kubota. But, after reading the "clearance" explanation, and the fact that the owners manual specifically omits 15W-40 as a recommended oil, I will stick with the recommended "SAE30, SAE 10W-30or 10W-40". But NOT Kubota brand (lowest bidder per their specs?).

Whew !!!!.....OK, Who makes the rated oils in Dino and Synthetic? It looks like Mobile 1 10W-30 meets the recommendation (API CF and CD). Any others?

 

[kkesler]

Are you running air cooled? If so, diesel rated oil has more of the high temp high pressure addititives in it that would work better. Water cooled is more controlled lower temp environment, and does not need the same additives.

Both. I run the Rotella in everything I have with 2 or 4 wheels.

 

[texasjohn]

I run Mobile 1 synthetic for diesel engines, 10W-30. Have also used Rotella T Synthetic.

 

[bravo36]

Used the Royal Purple stuff for my first 2 oil changes. Just noticed that our local WM now carries the Mobil 1 diesel oil. Might switch over to that or use the Rotella Syn. the next time around.

FWIW, I did 15 yr. in th U.S. Border Patrol in San Diego before moving back to Texas in '02. I was at a 500 man station (Brown Field) near the Otay Mesa border crossing, and we had a fleet of various vehicle to support that many agents in the field.

We switched over to Royal Purple (synthetic) for all the vehicle engines, and though we never had an engine failure, virtually every vehicle in the fleet developed oil leaks on their main seals. We had oil puddles all over the place. This was about 1998-2000, or thereabouts.

 

[Skyco]

Actually there aren't many true synthetics on the market nowadays, even the fabled Mobil 1 oils are now mostly non-synthetic in the true pre-lawsuit* sense. The Rotella T 5w-40 everyone raves about on many boards? A great oil but NOT a true synthetic. It used to be priced accordingly but they seemed to have edged up since they got everyone fooled

* Someone, I forget who, but I think it was Castrol, was sued by Mobil for claiming their oils were synthetic when they weren't. Mobil lost! The courts (note here-NOT oil experts) ruled the oil was tweaked enough they could call it synthetic even though it wasn't made from "scratch" like other synthetics. They basically turned an engineering term into a marketing term, caveat emptor!

 

[texasjohn]

I've heard that since synthetic is more "runny" than other oils that it will more easily find its way thru poor seals/gaskets.

Somewhere once I read that it is best to start a vehicle with synthetic... rather than put it into a high milage vehicle because the older vehicle is subject to leaks more.

I have made a personal assessment... having driven a Toyota to 300,000 mileson the original engine, no repairs at all, with only Mobile 1 in it... that I'd rather have an occasional drip than engine repairs... For years now I have put mobile 1 in all my vehicles... works for me... and, I go for very extended oil changes because other things in my life get in the way of changes at less than 10,000 miles or so.

That's just me, YMMV

 

[DiezNutz]

I like the synthetics, don't get me wrong, if for no other reason that extended oil change intervals on some machines. But I know a junkyard that has a few Rabbit Diesels in there with 400K and 600K miles on them. Since long before any of us ever heard of synthetic oil. Just something to ponder.

 

[Sully2]

... Even the new C7 Cat's manual states that in my area you can use a 10W/30 viscosity.

The reason why CAT went to recommending 10W-30 oils is because theur fuel injectors are operated by the engine oil pressure..etc..and with 15W-40 AT TIMES they were having priblems. Hence the switch to a "lighter" engine oil.

 

[DiezNutz]

Actually there aren't many true synthetics on the market nowadays, even the fabled Mobil 1 oils are now mostly non-synthetic...

This is true. Offhand I can't think of a synthetic that isn't fundamentally a petroleum base. None of this will matter a few years from now anyway if manufacturers & refiners get their way... non-synthetic won't even be offered anymore. There's not as much difference between the two anymore as there used to be, or asmost people think. One of the factors creating this push? Turbos. Big advantage synthetic has over conventional oil is extended temp range via better thermal breakdown resistance. Synthetics don't coke up turbo bearings and other parts of the engine when shut down hot, which is why you see more turbos being spec'd to run synthetic.

As far as the whole "don't break an engine in on synthetic?" Thing of the past. Anyone that's rebuilt an engine in last several years knows (or has learned the hard way through flat cams/leaky rings) that dino oil doesn't contain all the golden nuggets of zinc, manganese, etc. anymore that used to help with break-in, and it has many more of the anti-wear additives to make it more like synthetic. "Old-school" dino oil has pretty much gone the way of leaded gasoline. So these days the type of oil you use for break-in really doesn't matter as much as the assembly lube and the additives that either you or the factory puts into it. Don't take my word for it though; I would encourage anyone that finds this interesting to research for yourself.