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Does the 2500 5.7L have MDS?
I know the 2013+ RAM 2500 5.7's do not have MDS on them, just the 6.4's have MDS. Prior years I do not know about.
Then why would the 6.4 MDS use 0W-40?Exactly. My point would be that pre MDS Hemi vehicles including Durango and Grand Cherokees called for 5W-30 so I would argue it has less to do with being HD and more to do with is the engine MDS or not MDS...
Then why would the 6.4 MDS use 0W-40?

Ambient outside temps play a very insignificant part in oil performance. The only time it does is on the cold side not the hot. From the machinery lubrication website: An engine oil's operating temperature does not change significantly even in different ambient temperatures, so the recommended viscosity is quite consistent for various applications. The main difference is the viscosity grade "W," which relates to the starting temperature, as this will determine the lubricant viscosity, its pumpability and readiness to lubricate the engine. So whoever told you that thicker oil is needed if its hot outside is simply wrong.The state of CA has some guide lines on OCI because this state is quite concerned about the environmental impact of engine oil.
One of the guide lines says that driving at elevated ambient air temperatures is considered severe duty.
Have noticed the oil temperature increases with increase in ambient temperature, increase in ground speed, mountain upgrade driving with box payload or towing load.
Recently changed from 5w20 to 5w30 because central CA has quite high ambient temperatures during the summer months reaching well over 100F on a regular bases and do a fair amount of 6% upgrade driving. Have noticed no difference between the two oil grades, except the 5w30 runs slightly higher temperature than 5w20 on up hill climbing ~7F on one test.
Protection, in my opinion is all about running in the hydrodynamic boundary condition whether bearings, camshaft, timing chain, gear pump, piston rings, etc. Where there is basically no wear.
Once that hydrodynamic boundary layer is penetrated the parts are either in transition or basic boundary layer with no oil between the moving parts.
This condition is where the wear actually occurs.
The hydrodynamic boundary layer is lost based on load and oil viscosity.
The more viscous the oil the more difficult to break the hydrodynamic boundary layer at a given temperature.
If the engine is running 5w20 and the load does not exceed the oil film strength, no wear occurs.
If the load does exceed the oil film strength, the parts are now relying anti friction additives to reduce the wear rate.
In my opinion the increase in viscosity of 5w30 exceeds the operating temperature increase between 5w20 and 5w30.
So when the engine is subjected higher ambient temperature and bigger load the 5w30 will provide better protection against hydrodynamic boundary layer breakdown.
I know the 5w20 will get better mpg and the engine will run slightly cooler because of greater oil flow rate, but the film layer may break down under heavier load at elevated ambient temperatures. Why take a chance?
That is the reason the Ram 2500 with 5.7 recommends 5w30 because the truck is used by utility companies loaded down with lots of tools and equipment.
Today I'll made RodRam proud
Seriously I believe his filter research and trials are solid .
Look what I got today .
Haven't installed yet , when I do I'll post up any differences in oil pressures and comparison pictures of the eight hole Wix & the (i think ) 6 hole RP10-48 .
Not positive but after looking at the Wix , I'm thinking the 8 holes are a smaller O.D. than the fewer holes of the RP filter , this may compute to a lesser overall proportional difference than I was hoping for ( flow wise ) either way the coil ADBV verses the plate may be difference enough to at least consider the Wix over the RP ? Let's not forget ravens statement above about the spot welds though .
As I , syn , BBB aka Burla and many many others have said in the past 3700+ post this decision is to be made in the eyes of the beholder . In this case , I'm the beholder .
A LARGE portion of my decision will be made on my 5.7L s individual results with approx 650 miles on my current oil fill using the RP 10-48 , I'll be changing to the Wix XP filter and comping pressures , sounds and feel .
Today I'll made RodRam proud ��
Seriously I believe his filter research and trials are solid .
Look what I got today .
Haven't installed yet , when I do I'll post up any differences in oil pressures and comparison pictures of the eight hole Wix & the (i think ) 6 hole RP10-48 .
Not positive but after looking at the Wix , I'm thinking the 8 holes are a smaller O.D. than the fewer holes of the RP filter , this may compute to a lesser overall proportional difference than I was hoping for ( flow wise ) either way the coil ADBV verses the plate may be difference enough to at least consider the Wix over the RP ? Let's not forget ravens statement above about the spot welds though .
As I , syn , BBB aka Burla and many many others have said in the past 3700+ post this decision is to be made in the eyes of the beholder . In this case , I'm the beholder .
A LARGE portion of my decision will be made on my 5.7L s individual results with approx 650 miles on my current oil fill using the RP 10-48 , I'll be changing to the Wix XP filter and comping pressures , sounds and feel .
Today I'll made RodRam proud
Seriously I believe his filter research and trials are solid .
Look what I got today .
Haven't installed yet , when I do I'll post up any differences in oil pressures and comparison pictures of the eight hole Wix & the (i think ) 6 hole RP10-48 .
Not positive but after looking at the Wix , I'm thinking the 8 holes are a smaller O.D. than the fewer holes of the RP filter , this may compute to a lesser overall proportional difference than I was hoping for ( flow wise ) either way the coil ADBV verses the plate may be difference enough to at least consider the Wix over the RP ? Let's not forget ravens statement above about the spot welds though .
As I , syn , BBB aka Burla and many many others have said in the past 3700+ post this decision is to be made in the eyes of the beholder . In this case , I'm the beholder .
A LARGE portion of my decision will be made on my 5.7L s individual results with approx 650 miles on my current oil fill using the RP 10-48 , I'll be changing to the Wix XP filter and comping pressures , sounds and feel .
View attachment 72742View attachment 72743
Just for the record, this is the oil filter for the 6.4. As you can see, it has the coil spring.
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