Rethinking 5w-40 vs 15w-40 for my low use diesels

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I'm going to be the crazy outlier and say 10W30 HDEO, like Rotella T5 or similar. You get the cold cranking ability (T5 pour point/CCS Is very close to 5W40 T6) of a full syn, with a lower price tag. Unless you're pulling trailers over mountains in summertime, it's more than thick enough. Lots of new semis running it too!
 

wdn

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I use Delvac 1300 15W40 in my Kubota diesel tractor since I bought it new 20 years ago, and that is the only oil it has ever used. The tractor is used all four seasons and has plowed snow in -17F temperatures. I do keep it garaged and have a magnetic block heater available for really frigid temperatures but hardly ever use it.
 
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I've run Rotella T4 15w40 in my '17 RAM W/HO Cummins. Pretty much all it does is tow a heavy 5th wheel, and plow the driveway in the winter. I've started it below 0° F numerous times. It starts fine, and runs fine at those temps. Oil pressure comes up quickly. The block heater is rarely if ever plugged in.

The truck has been trouble free, and the engine is the last thing I'm worried about.
 
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I had a 21 degree start a couple weeks ago camping. In my well worn engine, it took a while to register pressure. I'm going to try 5w40 this winter.
 
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I know you don't have euro spec gas/diesel PCMO 10W40 but any HDEO available? I think euro 10W40s are now all group II/III, they're all SN rated.
 
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Then where would the group I oil be used, and where is the group II production capacity?

I don't think SN rating has anything to do with base oil.
 
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How bout good old 10w40 A3/B4? It will be blend and not full mineral, it will be high HT/HS, it is diesel spec, it is long life. And cheap.
 
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Low use especially, I’d have no issue running full synthetic. If not going by mileage, you could even do a bi or tri yearly OCI to offset cost.
 

JHZR2

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Low use especially, I’d have no issue running full synthetic. If not going by mileage, you could even do a bi or tri yearly OCI to offset cost.

Ive been doing 2-3 years for a while now. No big deal.

In cold weather 5W as is flows quicker.

I’m less concerned with cold weather, more concerned with after long sitting…

How bout good old 10w40 A3/B4? It will be blend and not full mineral, it will be high HT/HS, it is diesel spec, it is long life. And cheap.

I’d prefer an HDEO for these Diesel engines…

I've run Rotella T4 15w40 in my '17 RAM W/HO Cummins. Pretty much all it does is tow a heavy 5th wheel, and plow the driveway in the winter. I've started it below 0° F numerous times. It starts fine, and runs fine at those temps. Oil pressure comes up quickly. The block heater is rarely if ever plugged in.

The truck has been trouble free, and the engine is the last thing I'm worried about.

15w oils are ok to between 3-23F per the Daimler and other viscosity charts.

 
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Well aware of what the charts specify. I'm just saying what I've done. I'm talking -5° F at most. Colder, and I'd plug in the block heater, and likely run a 5w40. Never had a problem with the MDT and HDT trucks I owned at those temps with 15w40, either.
 

JHZR2

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I actually found two gallons of old rotella T6 5w-40 in my garage, so might as uwe use it…. It may be 10 years old, but the bottles are sealed.

I was surprised to see this at startup once the filter got saturated and pressure came up.

3BBDCDEB-32A9-4F0D-9D15-813459680908.jpeg


Typically these engines peg the needle at 3 bar when cold idling, but hot idle I typically see the needle drop to 1.5-2bar at idle. With any throttle at all the pressure pegs.

But I was surprised to see a lower starting out pressure on the oil I installed in there. The engine might have been slightly warm, but the oil was not.

Not sure if this is a concern or not.

Thoughts?
 
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No problem as long as the pressure gauge reads at least 1 bar at idle and is pegged before the engine reaches 1500 rpm. Do you notice a difference between different oils usually?
 

JHZR2

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How warm do you think it was outside when you started it? It's probably normal considering 5w40 needs less energy to pump so no need for that much oil pressure.
About 65F at most. My other 4 cyl version of this engine running 5w-40 (Schaefer’s) pegs at the start. I put 5w-40 rotella in (old stock), because I had it laying around.

Easier pumping is good, but less pressure I’m not so sure…
 
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