25 degrees & 15/40 rotella

[Egon]

Up until now the frozen north usually runs 15/40 oil winter and summer. Course most of us have block heaters too.

 

[big bubba]

Thanks guys on info. Do you have a engine hour benchmark (on a new diesel tractor) that you would feel comfortable switching from dyno to synthetic oil? The tractor has 130 hrs on it now with an excellent break in period. My experience has been (on new 2 cyl 4 cycle gas engines) that synthetic just doesn't seat those rings completely. But I like the 5/40 rating on Rotella synthetic. cheers bb

 

[Sully2]

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.

I did a heap of studying before I went out and bought oil to change my own...and arrived at this conclusion. I have a large Cummins diesel here at home and "Onan/Cummins" says that 5W-40 SYN is A-OK for their small diesels in their gensets...and also for their 500HP PLUS diesels for large truck applications...and since the Rotella 5W-40 EXCEEDS the "C" specs that Kubota states...then this oil was going to be "OK" for my usage..???

 

[RalphVa]

I've bought 5w40 Rotella and 0w40 Mobil 1. The manual for my tractor says 5w30 is okay, and that's what I use (in Mobil 1). I'd use 0w30 in it if I could get it. 0w flows A LOT better at low temperatures and is STILL MORE VISCOUS than probably your 40w at operating temperature. When 0w oils were being explored by our research outfit, some 0w synthetics were available. So, they put some cars in the -40 F/C (same at that temp) box and put transparently OHV covers on them and started them up after sitting overnight. Any oil but a 0w resulted in A LOT of smoking underneath the valve cover before oil got to it.

Ralph

 

[KeithT]

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

Yeah it make sense to go 5W-40 year round. I will not put enough hours on my tractor to have to change it more than once a year.

 

[Z-Michigan]

Ralph - I don't know if your JD has a turbo or not but I would avoid the Mobil 1 0W-40 if it does. That oil is OEM spec in my Jeep CRD but owners have found it seems to be associated with too much oil blowing through the turbo and getting into the intake/exhaust. I and many other CRD owners are using Rotella-T 5W-40 with great results. This could be a fluke for one specific vehicle, but just my 1 cent. The 0W-40 has a very dated "CF" rating as to additives for diesel engines, dating from the early 90's, and is really intended more as an oil for gasoline car engines than for diesel engines, even though it has that CF rating.

 

[MikeD74T]

The Shell site specs 15-40W for below 0F. None of their newer oils are touted as offering more cold protection, but may offer better milage. The only other thing I noticed was a recommendation to use 40W in Detriot Diesels down to 0F then switch to 15-40W for colder temps. I use 15-40W in my tractor that sees -45F & starts fine without knocking. I let it warm up for a while as all the hydraulics need warming also. MikeD74T

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