At work they are telling me they use Napa oil SAE 30 (API SM) oil in a approx 30 hp Kubota diesel engine. Diesel's are suppose to use "C(X)" oil the manual suggests CF to CG-4 depending on sulfer level of fuel. But figure the manual was written pre 2007 and CG- CI-4 plus and any LE oil would be ok.

How bad is it to run the SM oil. I say its not good especially on first oil fill to do it and oil will increase in oil viscosity due to soot faster but don't know how much faster. Or how hard to push management for the correct oil. You know they are going to say we have been using the SAE 30 SM oil for years and had no problem.

What do ya'll use for SAE 30 diesel oil?

NAPA SAE 30 HD engine oil and Castrol SAE 30 HD engine oil are both good oils. NAPA brand is manuf by Ashland Oils, same as valvoline. It is basically Valvoline in a cheaper container. Either is fine for things that SAE 30 is called for. I use SAE 30 in my old air cooled gasoline military 4x4 in the summer and 10w-30 when the winter sets in.

Don't know about running SAE30 in diesel. I would run what the manual says to run, not what someone else is telling you.

I RUN ROTELLA SYNTHETIC 5W-40 IN MY BX2200.. 300 + HOURS ON IT NOW AND NO PROBLEMS...

ARM



At work they are telling me they use Napa oil SAE 30 (API SM) oil in a approx 30 hp Kubota diesel engine. Diesel's are suppose to use "C(X)" oil the manual suggests CF to CG-4 depending on sulfer level of fuel. But figure the manual was written pre 2007 and CG- CI-4 plus and any LE oil would be ok.

How bad is it to run the SM oil. I say its not good especially on first oil fill to do it and oil will increase in oil viscosity due to soot faster but don't know how much faster. Or how hard to push management for the correct oil. You know they are going to say we have been using the SAE 30 SM oil for years and had no problem.

What do ya'll use for SAE 30 diesel oil?

The viscosity is no problem to match (says I could use multi viscosity too 10W-30 or 10W-40). I have the SAE 30 oil but the API designation is SM which is for a gasoline engine.

Its common around here for 15W-40 and SAE 40 to be diesel rated but I don't remember seeing SAE 30 (or 10W-30 or 10W-40 for that matter) as diesel rated.

I guess I could suggest use synthetic 5W-40 as a common diesel rated oil not too thick when its cold. Evidently 15W conventional oil is too thick when cold for the Kubota bearing clearances.

Delo 100 oils are SAE 30 and diesel rated but I haven't seen it at the local auto parts stores. I guess I need to go to an equipment dealer.

well mine started all winter even at -15 f. had to leave the glow plugs on a bit longer but it started..

arm

well mine started all winter even at -15 f. had to leave the glow plugs on a bit longer but it started..

arm

Arm you actually posted the first time while I was typing. It dawned on me that synthetic would meet the requirement.

I was mainly worried about the "SM" API rating.

It's not so much of an oil meeting the "Sx" rating; there are sevearl HDEO's that do.

As long as you choose a fluid that meets/exceeds the "Cx" criteria, then you'll be fine. The "SM" spark-ignition rating is superflous; it's not going to harm anything, but it is not the rating you should be concerned about. The lubricant you choose must be "compression ignition" rated, and meet the spec's in the Kubota manual.

I'm not greatly familiar with the Napa SAE 30 product. If it has a "Cx" rating that meets the required spec, you're ok for that application. If it is ONLY SM rated, it's the wrong application for a multitude of reasons. Unfortunately, many of the old myths and stigma's about lubricants die hard. While a straight 30 grade oil is likely ok to use, a multi-weight is a better all around choice, and needs to be of the proper desingation.

If "they" are telling at work to use a non-compression-ignition oil in a diesel just because it's a "heavy duty 30 weight", then "they" are flat out wrong.

I have a B7400. The manual calls for SAE 30 oil. I even checked with the local Kubota dealer. He has Kubota brand oil that is not Cx rated, just SAE 30.

I found that very interesting myself, but I'm not going to doubt what Kubota says to run in their engines.

I have a B7400. The manual calls for SAE 30 oil. I even checked with the local Kubota dealer. He has Kubota brand oil that is not Cx rated, just SAE 30.

I found that very interesting myself, but I'm not going to doubt what Kubota says to run in their engines.

Depends on who tells me and why. Some dealer rep or technician who heard from his manager or cousin that its ok doesn't cut it with me. Just because someone works somewhere and gets a uniform or title doesn't impress me. They need to be able to explain it to me.

dnewton3 I agree. I am trying to find a viscosity graph (not just a chart) that shows the cross over of multi grade oil and also has straight grade oil too.

I want to fully explain it to someone that SAE 30 and 15W-40 are 2 different viscosities when cold (and other temps too). And how 10W-30 and 10W-40 compare too. I just can't remember how it works.

To show a 5W-40 is equivalent would be good too.

Any one have a good link to a viscosity index graph.

I have a B7400. The manual calls for SAE 30 oil. I even checked with the local Kubota dealer. He has Kubota brand oil that is not Cx rated, just SAE 30.

I found that very interesting myself, but I'm not going to doubt what Kubota says to run in their engines.

On 2nd read I guess I over reacted a bit. Kubota oil may not have the API (American Petroleum Institute) cert. But be diesel rated too. If it is ISO rated or Japanese approved then OK but agree if its "Sx" oil then its not good enough with diesel soot.

OK I found this graph

http://www.widman.biz/Seleccion/Viscosidad/Conversiones/Graph/graph.html

and at 25C and above 15W-40 and SAE 30 are pretty similar for viscosity

IF I put in SAE 30 is 100 and 11 at -40 and 100C for the numbers and recalculate the graph. I found the viscosity of oil on Bob is the oil guy site.

My little b7100 calls for 10w-30 diesel oil- not real common.

My little b7100 calls for 10w-30 diesel oil- not real common.

Exactly ???? This might be one of those things lost in translation of manuals.

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But looking real close at the recommendation vs the viscosity index graphs 15W-40 appears ok.

This Kubota manual reads....

Above 25C SAE 30 or 10W30 or 10W40.
0-25C SAE 20 or 10W30 or 10W40
Below 0C SAE 10 or 10W30 or 10W40.

Since at operating temp xx40 weight is OK it depends on ambient temps for start up. 15W would be comparable to SAE 20 and probably be good for -5-10C. 5w-40 synthetic would cover everything (as usual).

I would not like to run SAE 20 or SAE 10 as they would be too thin at operating temp and I would definately push to use multi-viscosity for below 0C.

There are a few "reasonable" options.

A 10W-30 grade is good, and it can be found in a HDEO (diesel) oil. Rotella and Delvac both come to mind. In the midwest, you'll see these with some regularity during winter, but during summer, they are admittedly rare.

A 15W-40 grade HDEO is a good all around option as well. Very common in many brands, any time of the year. As long as you're not in long cold exposure operating environments, this would work fairly well, although longer cranking times might be a negative side effect compared to the 10W-30.

A 5W-40 "synthetic" is an option too. The only example that seems very reasonably priced that is very easy to obtain on short notice is the Rotella blue bottle. There are many other good brands such as Schaeffers that are close to the cost, and offer steller performance, but they are a delivered product. If you plan ahead, that's not an issue. But if you want walk-in purchase convenience combined with synthetic performance, Rotella Synthetic is one of the few options. Typically about any Wally World or farm supply store will carry this.

I checked my manual, and it says the same as far as viscosity that schiker posted:
Above 25C SAE 30 or 10W30 or 10W40.
0-25C SAE 20 or 10W30 or 10W40
Below 0C SAE 10 or 10W30 or 10W40.

However, that doesn't address the issue of API rating, only SAE grade.

I also read in my manual that I am to use an oil meeting API CD, CE or CF. Geez - those are OLD designations, and my L3430GST is a 2006 model. So either they haven't updated the info in the manuals in a L O N G time, or they just don't require a very refined fluid.

Doesn't really matter though. Today's CI-4, CI-4+ and CJ-4 fluids will function better anyway. So pick one of those, in a 10W-30 or 15W-40 and you'd be fine, depending upon weather norms for your area. Or, spend a bit more and get a 5W-40 synthetic. As always, the RTS comes to mind as a good performing, moderatly priced, easily available fluid.