I am looking for the best group III oil which holds it's viscosity best without shearing. I want to run it year round in my duramax and not just the winter. I heard that rotella's new T6 5w40 holds up a bit better to shearing than the older formulation. Anyone ever run Mobil 1's Mobil 1 Turbo Diesel Truck 5w40? I can get that stuff pretty cheap at Walmart. Chime in all!
Best 5w40 Group III oil?
- Thread starter Ponch
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i have run Mobil 1 Turbo Diesel Truck in my FX45, after several runs of Mobil 1 0w40 that just were a little bit dirtier than i like (the nissan VK and VQ engines are typically dirty). the Mobil 1 Turbo Diesel Truck was much more to my liking and it did better than the new Delvac1 ESP (which i am finishing up now). quite a few of the folks on miata.net have switched to the new Rotella T6, at my recommendation, and love it, but i haven't run it yet. the numbers are quite good, however, and it is also available at Walmart.
Surf the used oil analysis section and read.
5w40
Rotella
Delvac
Amsoil
Delo
VPB
all hold up well Mobil 1 Turbo Diesel Truck is great too.
5w40
Rotella
Delvac
Amsoil
Delo
VPB
all hold up well Mobil 1 Turbo Diesel Truck is great too.
Another vote for the Rotella T6.
dnewton3
Staff member
Speaking as a Dmax owner myself, I'll offer this advice.
You can seek the "best" group III (which is actually a small market niche overall for HDEO in 5w-40), but it won't matter much at all, because you haven't defined HOW you intend to use the oil, and what parameters it must meet in operation. BTW - most consider the Mobil 1 Turbo Diesel Truck to be a group IV PAO, and not a III, so you can rule that out, if you're strictly going to stick to the group III limit. The true reality is that they are ALL blends of some portion, and we often get into the minutia of the debate when these subtleties mean nothing in the real world performance of protecting the engine.
I suspec, in your area, you could run either a 15w40 or conventional 10w30 and be just fine. Peruse the used oil analysis (as suggested) and you'll see the Dmax is very easy on oil, and can endure a great deal with a wide range of products.
You lube selection has very little affect on the overall lifecycle of the equipment, AS LONG AS you stay within the OEM specs. You lube selection will, however, affect the lifecycle of the lube itself, depending upon many inputs and conditions.
I'll give you credit for at least setting out one parameter you want to meet (vis retention). But, that is a very small part of the overall picture. And, I can personally attest, that a lighter grade oil functions perfectly fine in the Dmax. Your quest for a "thicker" oil over a longer period is likely moot, depending upon your operating conditions.
Here's my specific example:
Last year I ran Rotella conventional 10w30 oil for 6k miles (about half of it with heavy towing), and it did a great job of protecting the engine (read via wear metals). The ONLY thing that happened was that it actually thickened up to a 40 grade. No big deal; likely due to the evaporation/oxidation of the oil over the harder use. I am now running a 15w40 Devlac 1300 to see if it will "thicken" past a reasonable point under the same conditions. Time will tell.
But consider how many PSD owners fear the shearing of the HEUI, and see the 15w40 shear down quickly. But, there really isn't any actual affect on wear!
My point? You might want "thicker" but you may not need thicker oil. The Dmax is so very easy on oil that it really doesn't matter as long as you stick to OEM specs. Any group III with a 5w-40 spread is going to shear some, but that does NOT mean that wear protection is automatically degraded. A 30 grade can go up to a 40 grade (my Dmax), and a 40 grade can go down to a 30 grade (may PSDs). But since most of today's diesel engines can operate safety on either a 30 or 40 grade, the shearing or thickening of the oil really doesn't matter much.
I see no direct evidence that oil viscosity has a direct relationship with wear in today's vehicles with today's oils, as long as the oil stays within the OEM directed range. Some people run 5w-40 oil where Ford spec's 5w-20. Ford backspec'd the 5w-20 where it used to call out 5w30 (the Cologne v-6 being the exception, AFAIK). So, can it really matter that much? Probably not.
To answer your question directly, there really are very few choices that are a "true" group III HDEO that you even have to choose from. The Rotella is probably the easiest by far to attain and afford. But if you don't run it out far enough to "pay back" your investment, it's a moot point.
You can seek the "best" group III (which is actually a small market niche overall for HDEO in 5w-40), but it won't matter much at all, because you haven't defined HOW you intend to use the oil, and what parameters it must meet in operation. BTW - most consider the Mobil 1 Turbo Diesel Truck to be a group IV PAO, and not a III, so you can rule that out, if you're strictly going to stick to the group III limit. The true reality is that they are ALL blends of some portion, and we often get into the minutia of the debate when these subtleties mean nothing in the real world performance of protecting the engine.
I suspec, in your area, you could run either a 15w40 or conventional 10w30 and be just fine. Peruse the used oil analysis (as suggested) and you'll see the Dmax is very easy on oil, and can endure a great deal with a wide range of products.
You lube selection has very little affect on the overall lifecycle of the equipment, AS LONG AS you stay within the OEM specs. You lube selection will, however, affect the lifecycle of the lube itself, depending upon many inputs and conditions.
I'll give you credit for at least setting out one parameter you want to meet (vis retention). But, that is a very small part of the overall picture. And, I can personally attest, that a lighter grade oil functions perfectly fine in the Dmax. Your quest for a "thicker" oil over a longer period is likely moot, depending upon your operating conditions.
Here's my specific example:
Last year I ran Rotella conventional 10w30 oil for 6k miles (about half of it with heavy towing), and it did a great job of protecting the engine (read via wear metals). The ONLY thing that happened was that it actually thickened up to a 40 grade. No big deal; likely due to the evaporation/oxidation of the oil over the harder use. I am now running a 15w40 Devlac 1300 to see if it will "thicken" past a reasonable point under the same conditions. Time will tell.
But consider how many PSD owners fear the shearing of the HEUI, and see the 15w40 shear down quickly. But, there really isn't any actual affect on wear!
My point? You might want "thicker" but you may not need thicker oil. The Dmax is so very easy on oil that it really doesn't matter as long as you stick to OEM specs. Any group III with a 5w-40 spread is going to shear some, but that does NOT mean that wear protection is automatically degraded. A 30 grade can go up to a 40 grade (my Dmax), and a 40 grade can go down to a 30 grade (may PSDs). But since most of today's diesel engines can operate safety on either a 30 or 40 grade, the shearing or thickening of the oil really doesn't matter much.
I see no direct evidence that oil viscosity has a direct relationship with wear in today's vehicles with today's oils, as long as the oil stays within the OEM directed range. Some people run 5w-40 oil where Ford spec's 5w-20. Ford backspec'd the 5w-20 where it used to call out 5w30 (the Cologne v-6 being the exception, AFAIK). So, can it really matter that much? Probably not.
To answer your question directly, there really are very few choices that are a "true" group III HDEO that you even have to choose from. The Rotella is probably the easiest by far to attain and afford. But if you don't run it out far enough to "pay back" your investment, it's a moot point.
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I would rather have an oil shear down one grade than thicken up one grade. Oxidation thickening is not a good thing.
Originally Posted By: Johnny
I would rather have an oil shear down one grade than thicken up one grade. Oxidation thickening is not a good thing.
same here
I would rather have an oil shear down one grade than thicken up one grade. Oxidation thickening is not a good thing.
same here
Thank you for the "in depth" reply....part of the reason for me wanting to run a xw40 was thinking I could gain some MPG"s with the synthetic....but for the cost difference it probably wouldnt be worth the extra cash for the more expensive 5w40. Did I read correctlt when you said the Mobil 1 Turbo Diesel Truck 5w40 is a group 4?
dnewton3
Staff member
Yes, most describe the Mobil 1 Turbo Diesel Truck at group IV.
Regarding the fuel savings from syns, it's not as exaggereated as most would lead you to believe. Most compainies will claim "up to" 3% or so, but that's under ideal conditions, etc.
You're far more likely to get a fuel savings from thinner oil; less pumping loss. Exactly the reason the OEMs have gone to thinner oils from the factory.
I agree with Johnny that oxidation thickening is the greater of two undesireable evils, but in my case, the UOA proof shows it wasn't detrimental in wear.
Regarding the fuel savings from syns, it's not as exaggereated as most would lead you to believe. Most compainies will claim "up to" 3% or so, but that's under ideal conditions, etc.
You're far more likely to get a fuel savings from thinner oil; less pumping loss. Exactly the reason the OEMs have gone to thinner oils from the factory.
I agree with Johnny that oxidation thickening is the greater of two undesireable evils, but in my case, the UOA proof shows it wasn't detrimental in wear.
Originally Posted By: Ponch
Did I read correctlt when you said the Mobil 1 Turbo Diesel Truck 5w40 is a group 4?
That's what people say but who knows what it is exactly.
Did I read correctlt when you said the Mobil 1 Turbo Diesel Truck 5w40 is a group 4?
That's what people say but who knows what it is exactly.
Shell Helix Ultra 5W40? Shell tech confirm Group III
Originally Posted By: Ponch
I am looking for the best group III oil which holds it's viscosity best without shearing. I want to run it year round in my duramax and not just the winter.
Rotella T6 is always an easy oil to find, excellent value.
Schaeffer 9000 is IMO a better value but not as easy to get (also some PAO content).
Mobil 1 Turbo Diesel Truck is typically a bit more difficult to find and more expensive than T6 but an excellent oil (although I did clean out my local autozone of all 12 quarts they had at $4/ea).
Valvoline Premium Blue Extreme is also good, but can be difficult to find.
Amsoil DEO & Red Line 5w40 - unknown composition, RL probably mostly group 5.
Valvoline Synpower 5w40 can sometimes be found at NAPA or Carquest on sale.
All of the above are 5w40s, mostly group 3 and would be excellent oils to run year round in the dirtymax.
I am looking for the best group III oil which holds it's viscosity best without shearing. I want to run it year round in my duramax and not just the winter.
Rotella T6 is always an easy oil to find, excellent value.
Schaeffer 9000 is IMO a better value but not as easy to get (also some PAO content).
Mobil 1 Turbo Diesel Truck is typically a bit more difficult to find and more expensive than T6 but an excellent oil (although I did clean out my local autozone of all 12 quarts they had at $4/ea).
Valvoline Premium Blue Extreme is also good, but can be difficult to find.
Amsoil DEO & Red Line 5w40 - unknown composition, RL probably mostly group 5.
Valvoline Synpower 5w40 can sometimes be found at NAPA or Carquest on sale.
All of the above are 5w40s, mostly group 3 and would be excellent oils to run year round in the dirtymax.
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