25 degrees & 15/40 rotella

   / 25 degrees & 15/40 rotella #1  

big bubba

Elite Member
Joined
Mar 7, 2007
Messages
3,280
Location
arkansas
Tractor
M8540
Seems to me 15/40 diesel grade engine oil is a bit sluggish at 25 degrees to keep engine protected? Or is a 10 min sufficient warm up on a tractor at that temp with that viscosity? Thanks! bb
 
   / 25 degrees & 15/40 rotella #2  
A large portion of engine manufacturers actually spec. 10W-30 for use in their engines these days. However people still use 15W-40. Its seems to be the same problem there was when multiviscosity oils came out. Many people were stuck on straight 40 weight oil and refused to use 15W-40, force of habit I guess.

My suggestion would be to check the owners manual and see what it spec's in your temperature operating range. You might be supprised to find your safe using 10W-30 year round.
 
   / 25 degrees & 15/40 rotella
  • Thread Starter
#3  
Yeah thanks, the dealer says that viscosity 15/40 for the tractor (kubota) is okay, but after changing the oil at 40 degrees, it flows like honey. Maybe there's enough residual on the internal parts till it reaches them on a cold start, but it concerns me. Esp on a new engine at 125 hrs. Is Rotella 0/30 rated for diesels? I'm probably neurotic w/too much time on my hands. round it goes....bb
 
   / 25 degrees & 15/40 rotella #4  
big bubba said:
Seems to me 15/40 diesel grade engine oil is a bit sluggish at 25 degrees to keep engine protected? Or is a 10 min sufficient warm up on a tractor at that temp with that viscosity? Thanks! bb

What does it say on the back of your oil jug? that should be accurate
and all engines should run for 10 minutes to warm up in my opinion
 
   / 25 degrees & 15/40 rotella #6  
Now that I know it's a Kubota your talking about I checked my Chek-Chart manual. Here's what it list for all Kubota's except the L2900, L3300, L3600 and L4300.

32 deg. to 77 deg. F 20W
Above 77 deg. F 30W
Below 32 deg. F 10W
Above 23 deg. F 15W/40
All temperatures 10W/30

Even the couple of models I listed above show you can use either 10W/30 or 10W/40 for all temperatures in those model tractors.

Like I said, check your manual. In the engine oil section it should have a chart like the one above showing which viscosity oils are suitable for different temperature ranges.
 
   / 25 degrees & 15/40 rotella #7  
I go 5W-40 synthetic Rotella in winter.
 
   / 25 degrees & 15/40 rotella #8  
Hiya,

Look to the manual for the correct grade and rating for the engine oil at the temps you expect before the next change. The people that developed the engine know a whole lot more about it's design, materials and needs than anyone else outside the factory. I have always used the lightest weight recommended in the manual for the temps I expect and since 1973 it's always been Amsoil for a brand. The synth oils flow really well at low temps I don't have to worry about dry starts until it hits about -50F or so at which point, I'm not going out on a tractor anyway. Too old for that....come to think of it, negative anything is too cold.. :D

As far as letting an engine sit at idle for 10 minutes to warm. I have found that in the cold weather that doesn't do much to help a Diesel to warm. I have always let the engine start with no throttle, let it idle for about a minute and then put a little throttle and load on it. They heat quicker and thus seal the rings and don't get excess fuel in the oil.

My 2 cents,

Tom
 
   / 25 degrees & 15/40 rotella #9  
KeithT said:
I go 5W-40 synthetic Rotella in winter.
Im getting ready to put the 5W-40 in my Kubora for year round service. It exceeds all the specs Kubota gives for oils anyway for a B3030 at least
 
   / 25 degrees & 15/40 rotella #10  
I'm wrestling with the oil spec too....I already have 15W-40 for my diesel pickup and it chaps me a little Kubotas, mine anyway, spec 10w-30.

The Kubota oil chart in my manual makes little sense--- they never show 15w-40 as an acceptable rating.

Now they show 10w-40 as acceptable so the 40 part must be ok, after all at operating temp a 10w-40 and 15w-40 should be the same viscosity.

So maybe they are worried about the low temp rating and consider 15w to be too thick- but then they show a straight 30 as ok above 77deg F, or a straight 20 as ok above 32deg F. We all know a straight 30 or even a straight 20 is thicker cold than a 10w or 15w...in theory anyway

All very strange and confusing...anyway I will stick with the 10W-30 during the warranty period just to be safe then will probably go with a 5w-40 or 15w-40.
 

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