Probably Overthinking

[Redhawk454]

The manual makes perfect sense. 5w-x for colder temps & 10w-x for hotter temps. You're looking at the high end 30 vs 40 but that is not what cummins/Nissan are looking at. They are putting more emphasis on the starting temp viscosities 5w vs 10w. I suffer from the same issue...overthinking.

dude they recommend the 10w-30 for CAFE reasons..

The manual doesnt do a good job at explaining things..

the reason owners manuals dont expound upon certain things is because it opens up more questions.

5w-40 will do a better job at carrying away a wear particle to the oil filter.

 

[Redhawk454]

The Ram owners manual in the diesel section isnt great..

I suppose you could run 10w-30 in the negatives if you plug in the block heater for a few hours..

 

[tnt_motorsports]

What causes shearing in a slightly heavier weight oil? Is it the 5W part or the 40?

My understanding is the difference between the 5 and the 40 and the additives they add to maintain that.I think the farther the spread the higher probability of shearing. I also think I had fuel dilution that didn’t help. I’m sure others on here will chime in who are far more knowledgeable.

Just my $0.02

 

[kschachn]

What causes shearing in a slightly heavier weight oil? Is it the 5W part or the 40?

Neither. It’s solely related to the quantity and quality of the viscosity index improvers used to create the multigrade. Oils don’t shear, VII do.

 

[whizbyu]

My understanding is the difference between the 5 and the 40 and the additives they add to maintain that.I think the farther the spread the higher probability of shearing. I also think I had fuel dilution that didn’t help. I’m sure others on here will chime in who are far more knowledgeable.

Just my $0.02

How do you get fuel dilution to account for the change in viscosity? Is it driving habits like being heavier on the accelerator? Prolonged city driving?

 

[tnt_motorsports]

How do you get fuel dilution to account for the change in viscosity? Is it driving habits like being heavier on the accelerator? Prolonged city driving?

Mine was in a diesel pickup. It tends to happen in the winter, when idling and due to how the emissions work on a 2012 Ram Cummins.

Just my $0.02

 

[Redhawk454]

Mine was in a diesel pickup. It tends to happen in the winter, when idling and due to how the emissions work on a 2012 Ram Cummins.

Just my $0.02

how long were you idling it for?

 

[fantastic]

how long were you idling it for?

engines need more fuel in the cold. This can & does add to the fuel delusion issue. Add in short runs & it's a sure thing.

 

[tnt_motorsports]

how long were you idling it for?

I let my truck idle in the winter prior to leaving work. I usually let the truck idle until the coolant temp is about 130F. I use the auto idle with the exhaust brake on around 1250RPM. It can take about 5-10 minutes for this to get to temp.

Just my $0.02