Oil guru's....a few months back I posted my great cold start experiences with rotella T6 5w40...just recentely I used my last free oil change coupon from the dealership where I purchased my duramax pickup from, and they refused to give me anything but a dino HDEO oil for my pickup (typical stealership) ......so I went with rotella triple protection CJ-4, 15w40 and let me tell you what...what a HUGE difference I noticed. Not just by sound or "feel" but this is the first time that I have ever seen my oil pressure gauge read over 100 psi at a cold idle (elevated idle mode). This was on a cold startup morning in michigan at zero degrees after sitting for 12 hours. I know that GM recommends 15w40 can be used down to zero degrees, but for the people out there who refuse to switch to a 5w40 oil for at least winter time in northern US states...take it from me from "real world" experience...do your engine a favor in this cold weather...and do a switch to something more suitable for cold. Less strain on batteries, faster flow to critical areas of engine and turbo, and less "racket"! I will run this oil as long as I safely can and then do a UOA to see how well this holds up. They gave me a carquest oil filter, and I purchased a "filtermag" also which snaps onto filter in case any of you havent heard of that product. After this run I plan to run the T6 5w40 next year and then do a UOA to compare the two oils as best as I can. I also purchased a fumoto drain valve which I feel is a great 25 dollar investment for those of you who do lots of UOA's Take care all!! -Poncho!
Rotella triple protection 15w40 cold weather start
- Thread starter Ponch
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A synthetic does have better flow at extreme temperatures compared to conventional.
When it gets really cold every little bit helps.
as a cost savings alternative consider a 10w-30
dnewton3
Staff member
Yes, I certainly agree that syn's flow better at cold temps.
However, your criteria of "racket" and pressure are not the ultimate measuring stick to judge by.
Go ahead and run your high end oils, and do several successive UOAs. I'll run my dino oils, and do my UOAs. I'll bet you a dime to a dollar that your wear metals are not statistically different from mine. Our environmental temps are very similar (Bay City to Indy); you only average 4 deg F lower than I do.
Are there differences between dino and syns at start up? Sure there are. Do they matter? Not really for most of us; they don't manifest themselves in real world wear.
What's that tell us? We can make some fair conclusions that perhaps the Dmax lube system is robust enough to function well and provide protection against wear, regardless of the common temps seen and viscosities used, irrespective of base stock. Simply put, the Dmax oil system is desgined well and works well; for the temps you and I see, your "perceived" gain does not equate to "real" gain in wear reduction.
Pressure is the resistance to flow. Just because the pressure goes a bit higher with dino oil at cold start does not mean things are not flowing at all. It just means they are flowing a bit slower. "Slower" is a relative term to the bearing. For an example, I'm going to pick some numbers from thin air, so don't nit-pick the math; it's the concept to understand here.
Say the dino oil flows at 10 gpm at cold start and the syn flows at 12 gpm at cold start; the syn clearly has less resistance and flows quicker. But if the engine only requires 7 gpm for safe oepration, either one will suffice. If the bearings only need a certain amount of volume per minute, anything over that is undeeded. Do you realize that while your oil pump displaces 100% of the flow it can produce (at least in a theorhetical sense; there is some hydraulic slip) and the filter sees 100% flow, the engine itself will dump off some oil at each opportunity along the way. The last orifice in line is the one you size the system for; as long as it gets sufficient flow and pressure, everything upstream is "over capacitized".
I, too, want good cold temp starts. One thing to consider is the cold cranking. Thinner oil allows the engine to crank quicker (to accelerate and sustain any stated rpm in less time), which is very important in a compression-ignition engine, as you know. But, that can be attained with thinner dino oil, as well as syns. We've already seen stated in other threads that the cold-cranking ability of Rotella T6 5w-40 and the T-5 10w-30 have essentially the very same cold crank start characteristics (thanks to Jim Allen for his research). Even thinner dino 10w-30 does better than 15w-40.
But, in a Dmax, they all do "well enough" to protect the engine to the same level. How can I claim this? UOAs, UOAs, UOAs ...
Look them all over. I challenge anyone to show me any statistically significant evidence where a dino was usurped in wear protection in a Dmax under "normal" circumstances (where normal is defined by temps at or above zero, with OEM OCIs, with fluids and filters meeting the OEM specs). Yes, syns flow better at cold temps. No, they really don't make a difference down to zero deg F in a Dmax, per GM/Isuzu. And there are a LOT of UOAs to prove it.
If I were in an area that averaged -25 deg F or lower for sustained periods, I'd be using the thinnest HDEO PAO I could find (5w-30), moreso because of the cold cranking issue than wear issue. But Bay City does not qualify for that condition. Your average low is 14 deg F. Your engine can successfully sustain temps down to zero with 15w-40 as the "preferred" OEM spec fluid. Should we really have the gall to think your eyeball/auditory experiment trumps the hundreds (if not thousands) of engineering hours, lab testing, and real world data that the Dmax has under it's belt?
You and I have had both agreement and disagreement over this issue. I'm not trying to start an argument. Your obervastions are valid; I cannot and will not take them away from you. I'm just trying to get you to understand that your experiment with Rotella 15w-40 and observations do not necessarily equate to real world concerns. And, I can personally attest to the fact that if you do want a bit quicker flow, and quicker cold start cranking, those can be had with dino 10w-30; it's what I run. I get the same starting performance, and the same wear protection, for a LOT less money.
Does your Dmax rattle a bit less, and crank over a bit quicker with syn in the cold? I'll agree it probably does. But does it matter to the engine? Nope; evidence suggests otherwise.
It matters to you; the engine couldn't care less.
However, your criteria of "racket" and pressure are not the ultimate measuring stick to judge by.
Go ahead and run your high end oils, and do several successive UOAs. I'll run my dino oils, and do my UOAs. I'll bet you a dime to a dollar that your wear metals are not statistically different from mine. Our environmental temps are very similar (Bay City to Indy); you only average 4 deg F lower than I do.
Are there differences between dino and syns at start up? Sure there are. Do they matter? Not really for most of us; they don't manifest themselves in real world wear.
What's that tell us? We can make some fair conclusions that perhaps the Dmax lube system is robust enough to function well and provide protection against wear, regardless of the common temps seen and viscosities used, irrespective of base stock. Simply put, the Dmax oil system is desgined well and works well; for the temps you and I see, your "perceived" gain does not equate to "real" gain in wear reduction.
Pressure is the resistance to flow. Just because the pressure goes a bit higher with dino oil at cold start does not mean things are not flowing at all. It just means they are flowing a bit slower. "Slower" is a relative term to the bearing. For an example, I'm going to pick some numbers from thin air, so don't nit-pick the math; it's the concept to understand here.
Say the dino oil flows at 10 gpm at cold start and the syn flows at 12 gpm at cold start; the syn clearly has less resistance and flows quicker. But if the engine only requires 7 gpm for safe oepration, either one will suffice. If the bearings only need a certain amount of volume per minute, anything over that is undeeded. Do you realize that while your oil pump displaces 100% of the flow it can produce (at least in a theorhetical sense; there is some hydraulic slip) and the filter sees 100% flow, the engine itself will dump off some oil at each opportunity along the way. The last orifice in line is the one you size the system for; as long as it gets sufficient flow and pressure, everything upstream is "over capacitized".
I, too, want good cold temp starts. One thing to consider is the cold cranking. Thinner oil allows the engine to crank quicker (to accelerate and sustain any stated rpm in less time), which is very important in a compression-ignition engine, as you know. But, that can be attained with thinner dino oil, as well as syns. We've already seen stated in other threads that the cold-cranking ability of Rotella T6 5w-40 and the T-5 10w-30 have essentially the very same cold crank start characteristics (thanks to Jim Allen for his research). Even thinner dino 10w-30 does better than 15w-40.
But, in a Dmax, they all do "well enough" to protect the engine to the same level. How can I claim this? UOAs, UOAs, UOAs ...
Look them all over. I challenge anyone to show me any statistically significant evidence where a dino was usurped in wear protection in a Dmax under "normal" circumstances (where normal is defined by temps at or above zero, with OEM OCIs, with fluids and filters meeting the OEM specs). Yes, syns flow better at cold temps. No, they really don't make a difference down to zero deg F in a Dmax, per GM/Isuzu. And there are a LOT of UOAs to prove it.
If I were in an area that averaged -25 deg F or lower for sustained periods, I'd be using the thinnest HDEO PAO I could find (5w-30), moreso because of the cold cranking issue than wear issue. But Bay City does not qualify for that condition. Your average low is 14 deg F. Your engine can successfully sustain temps down to zero with 15w-40 as the "preferred" OEM spec fluid. Should we really have the gall to think your eyeball/auditory experiment trumps the hundreds (if not thousands) of engineering hours, lab testing, and real world data that the Dmax has under it's belt?
You and I have had both agreement and disagreement over this issue. I'm not trying to start an argument. Your obervastions are valid; I cannot and will not take them away from you. I'm just trying to get you to understand that your experiment with Rotella 15w-40 and observations do not necessarily equate to real world concerns. And, I can personally attest to the fact that if you do want a bit quicker flow, and quicker cold start cranking, those can be had with dino 10w-30; it's what I run. I get the same starting performance, and the same wear protection, for a LOT less money.
Does your Dmax rattle a bit less, and crank over a bit quicker with syn in the cold? I'll agree it probably does. But does it matter to the engine? Nope; evidence suggests otherwise.
It matters to you; the engine couldn't care less.
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^^^^^^ Yeah, I like it....what he said. I too have let go of the "synthetic devil" and come to the light. It's saved me time, money, and somewhat of a headache.
Dave, Cummins.....love it!!!!
Dave, Cummins.....love it!!!!
I agree, in many cases, the only reason to go synth is for better cold starts. If that's not needed, it's often not worth the extra money.
Well said dave! I figured I would grab your attention with this rotella post.
Well, I think viscosity counts for as much as the base oil. Had you been running a 10W30 dine, I'll bet all the symptoms you described would have been reduced. My Ford tractor wouldn't crank over enough to start one winter while on 15W40 dino. Put 10W30 dino in it and she cranks like a champ and has fired up on colder days than when it was stymied by 15W40. A 10W30 grade works well in my small tractor and diesel pickup. I just got hold of a batch of 10W30 semi-syn, which has very good CCV, compared to straight dino 10W30 or 15W40, so I will use some of that next time around.
In the meantime, Ponch, plug that D-Max in!
In the meantime, Ponch, plug that D-Max in!
I've been starting my duramax all winter with many days of -25C and many of -30c all on Rotella 15w-40. I'd say 95% of all diesels up here run 15w-40 and I'd bet it accounts for 98% of dealership oil changes on diesels.
I've run 0w-40 Duron in the past, but I don't put enough miles on the truck in the winter months to get through a single OCI. Meanwhile, according to the owner's manual you shouldn't tow with anything but 15w-40, so when spring comes I'm faced with dumping a perfectly good sump of high priced synthetic. That's why I stick with conventional HDEO.
I should have a UOA coming out in the next few months for my conventional HDEO through what has been a very cold winter.
I've run 0w-40 Duron in the past, but I don't put enough miles on the truck in the winter months to get through a single OCI. Meanwhile, according to the owner's manual you shouldn't tow with anything but 15w-40, so when spring comes I'm faced with dumping a perfectly good sump of high priced synthetic. That's why I stick with conventional HDEO.
I should have a UOA coming out in the next few months for my conventional HDEO through what has been a very cold winter.
dnewton3
Staff member
Yes, we Dmax owners do have that pesky "use 15w-40" topic to contend with, for warranty issues.
But I can tell you that I use 10w-30 dino HDEO, I pull a travel trailer in the summer heat out west, in the Rockies, and my UOAs show the wear to be impecable. So much for the "gotta have 15w-40" mentality.
Is 15w-40 wrong to use? No. Is 10w-30 wrong to use? No. It's situationally dependent. If I were in realy cold areas where the preponderence of the temps were cooler rather than warmer, I'd use a thinner oil. If it were REALLY cold, I'd use a thinner PAO. If I were in areas where REAL heat were the issue and cold temps didn't exist, I'd use any quality 15w-40 I could find. The Mid-West gets to see a bit of both. We don't have the luxury of excluding one for the other.
The thing to understand is that GM recommends 15w-40 down to zero; I'm confident they have tests and data advocating it's safe. They also approve the use of 5w-40, and 10w-30. So, if one wants a bit "easier" starting and cranking, then there are two options. My experience and UOAs show that you can get the same effects of 5w-40 by using 10w-30, in the general Mid-West areas, for less money, and still have excellent wear while towing.
Ponch's experience is valid and true; I'm sure he experienced "better" starting and pressure with 5w-40 syn over 15w-40 dino. But, for the area he's in (which is very much like mine) he can get that same performance for way less money by simply getting dino 10w-30 HDEO, and still have excellent wear protection. Two roads to the same destination; one just costs less than the other.
But I can tell you that I use 10w-30 dino HDEO, I pull a travel trailer in the summer heat out west, in the Rockies, and my UOAs show the wear to be impecable. So much for the "gotta have 15w-40" mentality.
Is 15w-40 wrong to use? No. Is 10w-30 wrong to use? No. It's situationally dependent. If I were in realy cold areas where the preponderence of the temps were cooler rather than warmer, I'd use a thinner oil. If it were REALLY cold, I'd use a thinner PAO. If I were in areas where REAL heat were the issue and cold temps didn't exist, I'd use any quality 15w-40 I could find. The Mid-West gets to see a bit of both. We don't have the luxury of excluding one for the other.
The thing to understand is that GM recommends 15w-40 down to zero; I'm confident they have tests and data advocating it's safe. They also approve the use of 5w-40, and 10w-30. So, if one wants a bit "easier" starting and cranking, then there are two options. My experience and UOAs show that you can get the same effects of 5w-40 by using 10w-30, in the general Mid-West areas, for less money, and still have excellent wear while towing.
Ponch's experience is valid and true; I'm sure he experienced "better" starting and pressure with 5w-40 syn over 15w-40 dino. But, for the area he's in (which is very much like mine) he can get that same performance for way less money by simply getting dino 10w-30 HDEO, and still have excellent wear protection. Two roads to the same destination; one just costs less than the other.
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Thanks dnewton3 for your well reasoned, as always, opinion. Helpful as usual.
I will give the 10w-30 HDEO a try. It's easy to find out here. I have a similar climate to you but likely more extreme on the cold end of the spectrum.
My father in law (a farmer) has been using straight 30wt HDEO in his duramax engines since they came out in 2002 if I'm not mistaken. He's never had any problems. He doesn't worry about warranty for some reason and likes the convenience of using the same oil that he buys by the 55 gal drum for his farm equipment.
I will give the 10w-30 HDEO a try. It's easy to find out here. I have a similar climate to you but likely more extreme on the cold end of the spectrum.
My father in law (a farmer) has been using straight 30wt HDEO in his duramax engines since they came out in 2002 if I'm not mistaken. He's never had any problems. He doesn't worry about warranty for some reason and likes the convenience of using the same oil that he buys by the 55 gal drum for his farm equipment.
Originally Posted By: Ponch
...take it from me from "real world" experience...do your engine a favor in this cold weather...and do a switch to something more suitable for cold. Less strain on batteries, faster flow to critical areas of engine and turbo, and less "racket"! -Poncho!
I'll do one better, Poncho, take it from my "real world" experience..... those with diesels in the colder climates should put a crowbar in their wallet and buy an oil pan heater pad. I used one for 10 years, every winter, in Alaska. Just had 15w40 dino oil in the truck. No problems even down to the coldest I experienced.... -72F (not wind chill).
Oil pad heaters are relatively cheap, long lasting, easy to afix to the oil pan, and don't use a lot of juice. Even if you are using a 5w40 syn oil, having it warm at startup will get it throughout the engine quicker. When I park the semi at home for a couple of days in the coldest weather (coldest at my house in Iowa when I had the truck shut off, around -28F one time), I just plug in the block heater and the oil pan heater. Starts right up like a warm summer day. You can get an oil pan heater pad for no more than a hundred bucks and it will usually last the life of the engine.
Got em on my New Holland ag tractor, my Jeep Libery diesel, and my semi.
...take it from me from "real world" experience...do your engine a favor in this cold weather...and do a switch to something more suitable for cold. Less strain on batteries, faster flow to critical areas of engine and turbo, and less "racket"! -Poncho!
I'll do one better, Poncho, take it from my "real world" experience..... those with diesels in the colder climates should put a crowbar in their wallet and buy an oil pan heater pad. I used one for 10 years, every winter, in Alaska. Just had 15w40 dino oil in the truck. No problems even down to the coldest I experienced.... -72F (not wind chill).
Oil pad heaters are relatively cheap, long lasting, easy to afix to the oil pan, and don't use a lot of juice. Even if you are using a 5w40 syn oil, having it warm at startup will get it throughout the engine quicker. When I park the semi at home for a couple of days in the coldest weather (coldest at my house in Iowa when I had the truck shut off, around -28F one time), I just plug in the block heater and the oil pan heater. Starts right up like a warm summer day. You can get an oil pan heater pad for no more than a hundred bucks and it will usually last the life of the engine.
Got em on my New Holland ag tractor, my Jeep Libery diesel, and my semi.
dnewton3
Staff member
I agree; electric aids (pan heaters, block heaters, battery chargers) are fantastic. Presuming you are around electricity ...
Originally Posted By: 440Magnum
Originally Posted By: dtt004
A synthetic does have better flow at extreme temperatures compared to conventional.
A 5w40 flows better at extreme temps than a 15w40. I'm not sure synthetic has all that much (or anything) to do with it!
Synthetic 15w40s blow the pants off conventional 15w40s in the cold.
Originally Posted By: dtt004
A synthetic does have better flow at extreme temperatures compared to conventional.
A 5w40 flows better at extreme temps than a 15w40. I'm not sure synthetic has all that much (or anything) to do with it!
Synthetic 15w40s blow the pants off conventional 15w40s in the cold.
And more than anything, synthetic base stocks make it easier to make a shear stable 5W-40.
dnewton3
Staff member
Originally Posted By: rslifkin
And more than anything, synthetic base stocks make it easier to make a shear stable 5W-40.
Completely true.
Also, (nearly) moot.
I have yet to see a UOA where being slightly out of grade resulted in catastrophic wear conditions. In fact, we've seen the infamous PSD engines shear 40 grades down to 30 grades, and still have excellent wear.
I will fully agree that we don't want a 40 grade dropping below a 20 grade. But to see it drop to a mid-30 or even low-30, never seems to manifest itself in any actual damage, simply due to the moderate loss of viscosity.
And more than anything, synthetic base stocks make it easier to make a shear stable 5W-40.
Completely true.
Also, (nearly) moot.
I have yet to see a UOA where being slightly out of grade resulted in catastrophic wear conditions. In fact, we've seen the infamous PSD engines shear 40 grades down to 30 grades, and still have excellent wear.
I will fully agree that we don't want a 40 grade dropping below a 20 grade. But to see it drop to a mid-30 or even low-30, never seems to manifest itself in any actual damage, simply due to the moderate loss of viscosity.
Yup. In most cases, it's a non-issue. The only times it might be a problem would be throwing a conventional 5W-40 (or even wider spread) into a shear monster of an engine, and running it HARD, particularly if trying to stretch the OCI.
Correct me if I am wrong...but I didn't think anyone makes a conventional 5W-40 oil...they are all synthetic.
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