Oil & Fuel Viscosity

sandyc · Mar 8, 2013

Well here goes....time to start another battle.

I am approaching my first oil change and like with past tractors I have switched out from the dino to the synthetic. No big deal except I got some 5w-40 Mobil one turbo diesel truck oil. I looked up the specs in my manual for my B2620 and found they recommend 10w-30. OK, I'll check with Kubota.....they said they only recommend Kubota oil and I should check my manual. Hmmmmm, I'll check with Mobil about using the different viscosity and they said sure no problem. Now I am left with a nagging doubt as to who to put my faith in.
Anybody dealt with this situation before?

oldnslo · Mar 8, 2013

I would use what ever you are comfortable using. I used 5W-40 in my BX and now have it in my Branson. The 5W gives better cold start protection and 40w gets a little thicker when hot.

sandyc · Mar 8, 2013

thanks for the response....I agree that you should do what is comfortable to you. My gut was that Kubota was just doing the corporate CYA

Deano · Mar 8, 2013

oldnslo said:
I would use what ever you are comfortable using. I used 5W-40 in my BX and now have it in my Branson. The 5W gives better cold start protection and 40w gets a little thicker when hot.

I second that. I am using full synthetic 10w-30 valvoline synpower but will switch to rotella t6 on my next change. I am at 930 hours.

murphy1244 · Mar 8, 2013

Under warranty I would use what the manufacture advises to CYA.

Gale Hawkins · Mar 8, 2013

sandyc said:
Well here goes....time to start another battle.

I am approaching my first oil change and like with past tractors I have switched out from the dino to the synthetic. No big deal except I got some 5w-40 Mobil one turbo diesel truck oil. I looked up the specs in my manual for my B2620 and found they recommend 10w-30. OK, I'll check with Kubota.....they said they only recommend Kubota oil and I should check my manual. Hmmmmm, I'll check with Mobil about using the different viscosity and they said sure no problem. Now I am left with a nagging doubt as to who to put my faith in.
Anybody dealt with this situation before?

Follow the $$$ trail and see how it impacts advice.

5W-40 is a good option for most diesel engines that I have met.

WilliamBos · Mar 8, 2013

murphy1244 said:
Under warranty I would use what the manufacture advises to CYA.

They cant force you to use Kubota oil, Magnusson-Moss prevents that. But I think they could nail you on the viscosity if it does not meet the ambient temps. I know MF stated as long as it met the ambient temps, you are ok.

Gale Hawkins · Mar 8, 2013

Kubota Engine America - Compact Diesel Engines

Yes, many of our customers use 15W40 engine oil in their Kubota diesels.

sandyc · Mar 9, 2013

All great points. I am still under warranty so I wouldn't want to give the corporate types any ammo to decline a claim during that period. Maybe I'll just stick with the Kubota oil until the unit is not covered.

PHILIP8N · Mar 9, 2013

I believe 5w-40 to be a superior oil in many ways over a 10w-30 (C class oils), and is what I am running now, which is very similar to the T6 mentioned above (I run M1 5w-40). Some people mention warranty, I do not buy into that. Kubota would have to prove that a different viscosity caused the failure. An oil leak resulting in all loss of oil pressure, or a rod bolt coming loose and destroying an engine, are not viscosity related, it is assembly related. Plus, how many failures of there of Kubota engines, very few and far between. The way I look at it, I want to protect my engine right from day one, because it is going to be with me a long time after the short Kubota warranty runs out, and Philips lifetime warranty takes over. Philip.

PHILIP8N · Mar 9, 2013

I just re-read my 2009 Kubota manual. I must say, it is outdated, poorly thought out, and needs to be revised. It says: Temps above 77F, use SAE30, 10w30, or 15w40. Temps between 32F to 77F, use SAE20, 10w-30, or 15w-40. Temps below 32F, use SAE10w, 10w-30, or 15w-40. I use and suggest the attached viscosity recommendations from Caterpillar for off road engines. Philip.

creekbend · Mar 9, 2013

Gale Hawkins said:
Kubota Engine America - Compact Diesel Engines

Yes, many of our customers use 15W40 engine oil in their Kubota diesels.

Thanks for posting the Link.

WilliamBos · Mar 9, 2013

PHILIP8N said:
I just re-read my 2009 Kubota manual. I must say, it is outdated, poorly thought out, and needs to be revised. It says: Temps above 77F, use SAE30, 10w30, or 15w40. Temps between 32F to 77F, use SAE20, 10w-30, or 15w-40. Temps below 32F, use SAE10w, 10w-30, or 15w-40. I use and suggest the attached viscosity recommendations from Caterpillar for off road engines. Philip.

Thank you so much for posting tjis. I am amazed at the broad range thst 5W40 covers, and how limited 10W30 is.

Guessing it is safe to assume I can run 5W40 synthetic year round.

Gale Hawkins · Mar 9, 2013

Actually 15w-40 is to only weight most people have to consider with a diesel tractor and is the only weigh needed if on uses a block heater in freezing weather.

WilliamBos · Mar 9, 2013

Gale Hawkins said:
Actually 15w-40 is to only weight most people have to consider with a diesel tractor and is the only weigh needed if on uses a block heater in freezing weather.

15W40 is not recommended for winter use up here, just too thick. Even GM recommends 5W40 in the winter months up here.

sandyc · Mar 10, 2013

Well, I happen to look at the gallon jug I have of the 05W-40 and it says "recommended as replacement for 15w-40". So, Kubota allows 15w-40 according to my manual then I guess I can use it. Maybe the synthetics have a wider range or something. At least 60-75% of my tractor use is during the winter months (in Maine that's Sept thru June) so I am going to opt for the Mobil 1 as it would appear to have some good cold properties.

WilliamBos · Mar 10, 2013

sandyc said:
Well, I happen to look at the gallon jug I have of the 05W-40 and it says "recommended as replacement for 15w-40". So, Kubota allows 15w-40 according to my manual then I guess I can use it. Maybe the synthetics have a wider range or something. At least 60-75% of my tractor use is during the winter months (in Maine that's Sept thru June) so I am going to opt for the Mobil 1 as it would appear to have some good cold properties.

Is that on an M1 Jug?

sandyc · Mar 10, 2013

yup...it's on the 05W-40 jug. Amazon has a picture of it as well!

Gale Hawkins · Mar 10, 2013

For a working tractor it is not the 0, 5, 10 or 15W that is of consideration but the last number. For most diesel engines as long as it is 40 then what becomes before it is a non issue if is recommended for your temperature zone.

kuboman · Mar 10, 2013

Unless you spend a lot of time maxed out in hot climates a 30 weight oil is ample. Most of these machines spend their lives at not much more than idle. All a heavy oil does is cause internal engine drag and fuel efficiency.:2cents: