Oil - Another "why" question

[RjCorazza]

In my area I may see single digit temps and have to use the tractor. My previous L3410 got 5w30 for 15 years. I decided on 5w40 for the new L4060 because my preferred oil brand does not offer a CJ4 spec oil in 5w30. Any of the weights you list will be fine, just make sure the oil meets whatever specs your tractor and emissions systems require.

 

[Beltzington]

"(Or should I just stop worrying about this and start thinking about problems I can solve like global warming)"<<<Yes exactly, get rid of your diesel guzzling tractor and switch over to a battery powered tractor and we can all live in harmony, sit around the battery powered camp fire and sing Kumbaya, no more worrying the brain numbing kunfusing motor oil numbers and diesel fuel color., I'll behind you all the way..............

My Deere runs forever on a few drops of diesel, maybe time to upgrade. Sorry for your pain.

 

[Oldpath05]

Sorry for what pain. pain in back, pain in the foot, or pain in the neck, some people have no sense of hummor:thumbdown:

 

[Copperhead]

While true, a 5w40 will give you the best of all operating temp conditions, it is also less shear stable than a 10w30 or 15w40. It requires more viscosity improvers, which can shear under extreme pressure. It is a balancing act. Yes, even a PAO synthetic 5w40 requires some viscosity improvers. Now it is true, there are some PAO 10w30 oils that don't require viscosity improvers.

I have been using a 10w30 syn blend in my commercial semi truck for quite a while. Better used oil samples than I got with a 15w40 in the same motor. 540,000 miles on it now, and it is a factory reman motor. Mater of fact, the same 10w30 HDEO CJ-4 / SM syn blend that goes into my Detroit 12.7L motor is also the same oil I use for almost everything else i own from portable generators right on up thru my CUT. Winter, Summer, it doesn't matter.

One has to factor hydrodynamic and boundary lubrication, shear stability, along with characteristics of the add pack component formulation in all this. Weight alone does not give the complete picture. Both synthetic 10w30 and blend 10w30 oils have cold flow pour points that are within a few degrees of any 5w40. Unless one is in the interior of Alaska or the harsher Canadian provinces, (or a special application engine), a 10w30 will fill the need of just about anyone. I run my semi thru the Dakotas, MN, Wisc, Mich, just about all the midwest all winter long on a 10w30 (and I shut the motor off at night when I stop for a break). Same oil gets used to pull the same loads in 100F ambient temps also. The engine uses about 2-3 qt in 22,000 miles. It holds 40 qt. Not bad for a 2000 factory reman motor with over half million miles on it after the reman.

 

[DEWFPO]

I once had a car with twin turbos and a small 6 cylinder gasoline engine with a manual transmission. It also had an oil temperature gauge on the dashboard. On long hard pulls up over the continental divide in Colorado the engine oil temp would hit 250F even when coolant temps were at 195. The owner's manual said that when engine oil temps hit 250F you should get your foot out of the turbos to allow it to cool down, which it would do fairly quickly. The oil spec'd for that engine was dino 5w30. The oil was always black even within a few days of an oil change. That was 13 years ago. I was surprised the manufacturer (AUDI) didn't spec synthetic oil for this application.

DEWFPO

 

[CurlyDave]

Thanks for the comments, I always go through this every time I due my annual service on the tractor. I think I may have asked my question poorly, so let me try again.

If I know I will never be operating below 0F or above 105F is there a best weight oil? Synthetic 5-40, 10-30, or Dino 15-40. Or should I just stop worrying about this and start thinking about problems I can solve like global warming

There is an answer, and it is very complicated. Way back when, from '67-'72, I was in graduate school and my thesis advisor was a rheologist (a guy who studies flow of fluids). Oil is not a simple fluid, and the viscosity enhancers they add have some very unexpected effects. One of these is called the Weisenberg effect. If you do the math, and believe me, it makes calculus look like a Sunday school picnic, there is a force which tends to center a shaft in a journal bearing caused by the viscosity enhancer. This obviously reduces wear.

Bottom line: the wider the range of viscosity the higher this force is. Other things being equal 5W-30 is better than 10W-30.

 

[dragoneggs]

There is an answer, and it is very complicated. Way back when, from '67-'72, I was in graduate school and my thesis advisor was a rheologist (a guy who studies flow of fluids). Oil is not a simple fluid, and the viscosity enhancers they add have some very unexpected effects. One of these is called the Weisenberg effect. If you do the math, and believe me, it makes calculus look like a Sunday school picnic, there is a force which tends to center a shaft in a journal bearing caused by the viscosity enhancer. This obviously reduces wear.

Bottom line: the wider the range of viscosity the higher this force is. Other things being equal 5W-30 is better than 10W-30.

Curly, thanks for taking me back to my fluid dynamics classes and the reason I drank a lot of beer in college. Not sure which was worse the hangover or the math headache. :laughing:

 

[bdog]

Thanks for the comments, I always go through this every time I due my annual service on the tractor. I think I may have asked my question poorly, so let me try again.

If I know I will never be operating below 0F or above 105F is there a best weight oil? Synthetic 5-40, 10-30, or Dino 15-40. Or should I just stop worrying about this and start thinking about problems I can solve like global warming

In those conditions any of the three would work fine. The 5w40 would technically be the best but it certainly isn't necessary and the others would be fine. If I were making the choice I would look at the temps you will operate in. You said you won't be out of the 0-105 window but which end are you likely to be closer to? If the cold end go 10w30 if the high end 15w40. Being you are in Georgia I would think probably the 15w40. I live in Texas and I buy 15w40 by the drums.

 

[RalphVa]

Use a good 5w40 oil to fill in all temps on that chart of yours. Think synthetics have little to no VI additive to do this.

You want the low 1st # to get oil to the top end on startups. That's when most wear occurs. A 15w oil will take a second or so longer to get up there, vs. a 5w or 0w oil.

Ralph

 

[Beltzington]

Bottom line: the wider the range of viscosity the higher this force is. Other things being equal 5W-30 is better than 10W-30.

This horse may still be alive so let me kick it a few more times. I'll differ the math to better minds, I always did well in college but I had to work hard at it. Based on your summary I'm curious if 5w-30 is better than 10w-30, wouldn't 5w-40 be even better? Specifically I am wonder if 40 weight is just to heavy for my operating envelope. Although anecdotal evidence seems to indicate otherwise.

Thanks folks.