Best engine oil weight?

[MossyDell]

This makes so much sense. Then I read someone remind us that engines are now made so tight and are designed for lightweight oil, so that heavier oil hurts them. That's scary! Then others say it's just for mileage, at the cost of durability. And then I recall how synthetic oil pours like water and wonder again if heavier oil is so bad. But then there's the "90 percent of wear occurs at startup, so use the lightest oil" and I am unsure again.

Whatever is true for car manufacturing, I wonder if we can assume the same for tractors. My B2601 manual still lists the typical range of 30 and 40 weights. And I remember an old man who commercially bush hogged with his little 24 hp Kubota and ran straight 50 weight. That was in the '80s, and it surely was not synthetic oil, which I believe doesn't need to be as heavy to offer protection.

Anyway, thanks mangler for trying to cut through all this.

I 'm sure if you change your oil diligently, never lug your engine, never overheat it, and trade-in the car in at 100k miles you could be fine with 0W20. But why take the chance? I consider oil as one of the very few aspects of car reliability I can actually influence. So I like to do what I can, within reason. Viscosity switch is certainly within that envelope.

 

[MossyDell]

A p.s. to my post above. My B2601 manual strongly recommends the use of Kubota's synthetic Super UDT transmission fluid for "enhanced ownership experience" and "superior performance and protection."

Engine oil type is not specified, just weights:

Above 77 F = SAE30, 10w-30, or 15w-40
14 to 77 F = same
Below 14 F = 10w-30

 

[DEWFPO]

I believe that most manufacturer's engines (of a specific type) for the most part are manufactured in one factory. That engine is then used worldwide under the gamut of operating conditions. For the same engine (presumably the same manufacturing tolerances) you will see a wide variety of engine oils specified depending on where they are sold. It appears to me that operating conditions are the main driver in spec'ing an oil for a particular engine. If you look at USA spec'd engines vs. EU spec'd engines you will see a difference. The USA spec'd engines suggest lighter oils than the EU spec'd engines. Heck, here in the US/Canada, a Dodge Hemi 5.7 is spec'd for a 5W20 engine oil, the stroked (higher performance version) of the 5.7 Hemi is the 6.1, 6.2 and 6.4L Hemi's. They REQUIRE 0W40 synthetic engine oil changed every 6 months or 5000 miles, period. No dicsussion if you want your warranty to stay in tact. In fact they strongly advise a natural gas based 0W40 synthetic oil only. I do realize that on engines (primariy gas) that are equipped with Variable Valve Timing, the oil thickness (at a given temperature and rpm) are the primary control mechanism for the camshaft phaser(s).

DEWFPO

 

[mangler]

A p.s. to my post above. My B2601 manual strongly recommends the use of Kubota's synthetic Super UDT transmission fluid for "enhanced ownership experience" and "superior performance and protection."

Engine oil type is not specified, just weights:

Above 77 F = SAE30, 10w-30, or 15w-40
14 to 77 F = same
Below 14 F = 10w-30

If you find a good 10W30 diesel oil, use it.

I could not, and I have basically the same weight recommendations from Kioti, so I am going to run 15W40 Amsoil signature series synthetic until the warranty is up. Very good blend of high high temp viscosity and decent low temp viscosity (for a 15W40). I already convinced myself that anything below -10C I'll just use the bloc heater.

If it was not for fear of arguing about leaks (under warranty) i would go with Mobil Delvac ESP 0W40. Not cheap either in these parts btw.

PS As far as i have read, super UDT is 5W30 equivalent, and UDT is 10W30. You get the most gains from super UDT below freezing, quicker start up, smoother when cold etc. Bottom line if they allowed UDT, I could get it cheaper and I lived in Va like you, I would use UDT.

 

[PILOON]

In conversation with a petroleum engineer I was told that diesel oil in a gas engine was good in that the additives for diesel would only be helpful and not detrimental.

Also non detergent oil was better for usage in lieu of hydraulic fluid, and actually specified in some heavy equipment.

 

[MossyDell]

If you find a good 10W30 diesel oil, use it.

I could not, and I have basically the same weight recommendations from Kioti, so I am going to run 15W40 Amsoil signature series synthetic until the warranty is up. Very good blend of high high temp viscosity and decent low temp viscosity (for a 15W40). I already convinced myself that anything below -10C I'll just use the bloc heater.

If it was not for fear of arguing about leaks (under warranty) i would go with Mobil Delvac ESP 0W40. Not cheap either in these parts btw.

PS As far as i have read, super UDT is 5W30 equivalent, and UDT is 10W30. You get the most gains from super UDT below freezing, quicker start up, smoother when cold etc. Bottom line if they allowed UDT, I could get it cheaper and I lived in Va like you, I would use UDT.

Mangler, 30 years ago I was using Mobil 1 10w-30 in my little Kubota tractor. It met the specs for diesel. This was before their diesel version oil now sold. I'm pretty sure I used it right up until 10 years ago when I sold my JD and went tractorless for a decade.

I get the impression from these boards that Mobil 1 for cars must no longer be C rated. Or is it just because there's now a diesel version? Has anyone looked?

 

[mangler]

Mangler, 30 years ago I was using Mobil 1 10w-30 in my little Kubota tractor. It met the specs for diesel. This was before their diesel version oil now sold. I'm pretty sure I used it right up until 10 years ago when I sold my JD and went tractorless for a decade.

I get the impression from these boards that Mobil 1 for cars must no longer be C rated. Or is it just because there's now a diesel version? Has anyone looked?

Look, I'll admit I am very spec centric when it comes to oil. Ok, when it comes to everything. Not sure if Mobil 1 was different back then. These days it's an ok synthetic at a mid to premium price. But last i looked the TBN for vanilla gasoline Mobil 1 was too low for any kind of real diesel service. Their technical data sheet is also skimpy on details (maybe less Motor Trend ads, more work on your TDS). Last I looked TBN was like 8.1 to 8.45 for "gasoline" rated Mobile 1 10W30. I prefer something around 10-12 TBN for a diesel oil (TBN is the total base number, which measures the ability of the oil to prevent become acidic in service, which is very bad for wear).

If you dump your oil every 3k miles, it would likely be fine. Looks like the 10W30 is still CF rated(pre-2009 diesel engine, light duty). You also have to be careful with the fancy new DPF engines, some really good oils from the past are not recommended anymore, because the additive packages can play havoc on the emissions equipment.

 

[DMW]

If you find a good 10W30 diesel oil, use it.

I could not, and I have basically the same weight recommendations from Kioti, so I am going to run 15W40 Amsoil signature series synthetic until the warranty is up. Very good blend of high high temp viscosity and decent low temp viscosity (for a 15W40). I already convinced myself that anything below -10C I'll just use the bloc heater.

If it was not for fear of arguing about leaks (under warranty) i would go with Mobil Delvac ESP 0W40. Not cheap either in these parts btw.

PS As far as i have read, super UDT is 5W30 equivalent, and UDT is 10W30. You get the most gains from super UDT below freezing, quicker start up, smoother when cold etc. Bottom line if they allowed UDT, I could get it cheaper and I lived in Va like you, I would use UDT.

15 years ago the debate was Esso XD-3 Extra 0W40 or Amsoil at BTOG. It was only marketed in Canada by Imperial oil. I believe it was rebranded as Mobil Delvac. Annual oil changes, 800hrs in 15 years, never had to add any oil between changes (23hp,3L fill). Usually grab a couple jugs when on sale at Canadian Tire. Last ones I got in October for $27/jug, regularly goes on sale. Tech sheets for Delvac 0W40 and Amsoil Signature Series 0W40 are pretty well identical.

 

[mangler]

15 years ago the debate was Esso XD-3 Extra 0W40 or Amsoil at BTOG. It was only marketed in Canada by Imperial oil. I believe it was rebranded as Mobil Delvac. Annual oil changes, 800hrs in 15 years, never had to add any oil between changes (23hp,3L fill). Usually grab a couple jugs when on sale at Canadian Tire. Last ones I got in October for $27/jug, regularly goes on sale. Tech sheets for Delvac 0W40 and Amsoil Signature Series 0W40 are pretty well identical.

I remember XD-3, used it extensively. Excellent oil, I remember buying my last 4l jug at Walmart for $21.79 Canadian (no a sale). Now I have to pay at least 100% more for the rebrand (Delvac ESP). At that price you are in Amsoil territory, and don't have to find a fuel depot with Amsoil (I've been getting my Delvac ESP at Dowler-Karns).

Good to know it is at Canadian Tire, I'll check it out and wait for the sales, I have never seen it at 27$. I still use it on all my my air cooled small engines. I'll probably use it when I am out of warranty on my tractor, but right now I'll stick with Amsoil 15W40. They seem to carry only 0W40 and 5W40 Delvac ESP at CT, which is a bit too thin cold per the "manual".

 

[John0829]

When the prices of "other" oils got to within a dollar or two of Amsoil, plus I could have it delivered to my door in a couple of days without having to brave the idiots in stores I went full Amsoil in everything. It is a premium lubricant that does what it is intended and I don't have to always be checking the spec sheet to be sure it meets the needs of my vehicles/equipment because the manufacturer decided to change the formula like the Mobil 1 mentioned. And I was a big Mobil 1 user at one time.