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Using 10W-30 over 15W-40 & 5W-40
- Thread starter -SyN-
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As for fuel dilution, just to put some numbers up: Starting 100C viscosity is at 12cSt for Duron 10w30. 24,238km and 2.87% fuel dilution. Viscosity was sitting at 11.47cSt. Barely took a hit, still well within Cummins condemnation limits for viscosity and fuel (max 5%).
The 6.7 ISB has a liquid/liquid oil cooler, a massive rad and fan. During my heavy towing, trans, coolant and oil temps are easily held in check, which negates the need in my case for a thicker oil to maintain viscosity (if it even matters)under high heat and stress.
The 6.7 ISB has a liquid/liquid oil cooler, a massive rad and fan. During my heavy towing, trans, coolant and oil temps are easily held in check, which negates the need in my case for a thicker oil to maintain viscosity (if it even matters)under high heat and stress.
-SyN-
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Thanks for your input Brian! As well as the rest of you.
While towing a 11-12K lb enclosed trailer with ambient temp @ 95*F I seen 244*F oil temp w/Schaeffers 5W-40.
So far that’s the highest I’ve witnessed so far.
The 6.7L right now is sporting barely 2400 miles.
While towing a 11-12K lb enclosed trailer with ambient temp @ 95*F I seen 244*F oil temp w/Schaeffers 5W-40.
So far that’s the highest I’ve witnessed so far.
The 6.7L right now is sporting barely 2400 miles.
Originally Posted By: -SyN-
Thanks for your input Brian! As well as the rest of you.
While towing a 11-12K lb enclosed trailer with ambient temp @ 95*F I seen 244*F oil temp w/Schaeffers 5W-40.
So far that’s the highest I’ve witnessed so far.
The 6.7L right now is sporting barely 2400 miles.
Pulling our 4.8k lb (dry) Travel Trailer I've seen oil temps of 260°F w/ M1 TDT 5w40 in our Ecodiesel 3.0L.
That made me want a higher HTHS. So I switched to a 15w40 Synblend with 4.3 instead of the 5w40 Full Synthetic with 3.8.
Thanks for your input Brian! As well as the rest of you.
While towing a 11-12K lb enclosed trailer with ambient temp @ 95*F I seen 244*F oil temp w/Schaeffers 5W-40.
So far that’s the highest I’ve witnessed so far.
The 6.7L right now is sporting barely 2400 miles.
Pulling our 4.8k lb (dry) Travel Trailer I've seen oil temps of 260°F w/ M1 TDT 5w40 in our Ecodiesel 3.0L.
That made me want a higher HTHS. So I switched to a 15w40 Synblend with 4.3 instead of the 5w40 Full Synthetic with 3.8.
Originally Posted By: Dak27
I also run a 12.7 Detroit Series 60 motor in my semi. I've been using 15W40 Phillips 66 Guardol semi-synthetic for the past few months. Because I pull quite a bit of heavy loads out of Idaho, which put my gross vehicle weight close to 80,000 lbs, I feel better about running a heavier oil for the majority of the year, especially when the outside temperatures are very warm. My loads frequently have me going into Texas and across the South.
I do use 10W30 in the coldest months of the Winter. I'll be using Guardol 10W30, starting in late November. I'll switch back over to 15W40 either in late March or early April. I notice the 10W30 does help for quicker cold weather startups.
I also pull some heavy loads. Last two weeks, nothing in the box under 43K. Same stuff for my customers I normally pull. The first year I tried the 10w30, I did as you mention... used 15w40 in summer. Then the following year, I did 10w30 all year. No indication either via oil pressure or used oil sample that it was a problem using 10w30 in the heat of summer pulling heavy loads. Detroit's Lube Manual does not lay out any variables in ambient temp regarding using 10w30 vs 15w40. 10w30 is allowed right on up thru the ranges for the 40 weights irregardless of load in the motor. It is just that so many of us have been conditioned to use 40 weights that it is hard to wrap our minds around the idea that a 10w30 would do the job just fine. I have figured it out, so it doesn't bother me anymore.
I also run a 12.7 Detroit Series 60 motor in my semi. I've been using 15W40 Phillips 66 Guardol semi-synthetic for the past few months. Because I pull quite a bit of heavy loads out of Idaho, which put my gross vehicle weight close to 80,000 lbs, I feel better about running a heavier oil for the majority of the year, especially when the outside temperatures are very warm. My loads frequently have me going into Texas and across the South.
I do use 10W30 in the coldest months of the Winter. I'll be using Guardol 10W30, starting in late November. I'll switch back over to 15W40 either in late March or early April. I notice the 10W30 does help for quicker cold weather startups.
I also pull some heavy loads. Last two weeks, nothing in the box under 43K. Same stuff for my customers I normally pull. The first year I tried the 10w30, I did as you mention... used 15w40 in summer. Then the following year, I did 10w30 all year. No indication either via oil pressure or used oil sample that it was a problem using 10w30 in the heat of summer pulling heavy loads. Detroit's Lube Manual does not lay out any variables in ambient temp regarding using 10w30 vs 15w40. 10w30 is allowed right on up thru the ranges for the 40 weights irregardless of load in the motor. It is just that so many of us have been conditioned to use 40 weights that it is hard to wrap our minds around the idea that a 10w30 would do the job just fine. I have figured it out, so it doesn't bother me anymore.
-SyN-
Thread starter
TT : Thanks for sharing all your experiences!
Really just thinking of adding 2 gals of Ultra 10W-30 with my 1gal 9000 5W-40 & call it a day with my Fleetguard LF 9028.
Really just thinking of adding 2 gals of Ultra 10W-30 with my 1gal 9000 5W-40 & call it a day with my Fleetguard LF 9028.
Thanks, TT. Did you notice higher oil temperatures or coolant temperatures in the hottest summer months using 10W30? I ran Delo XLE 10W30 into early May last year, and my gauges showed slightly higher temperatures. Nothing excessive than I was used to seeing, but I felt better about going back to 15W40 and my temperatures went back to what I was accustomed to seeing.
I plan on using Dyson Analysis shortly. I'll have UOAs ran on both 15W40 and 10W30, and see how the numbers compare. If there's a benefit to running 10W30 year round, which I assume would be a tiny bit of an increase in mpg compared to 15W40, I'll strongly consider it. Thanks for sharing your knowledge, I very much appreciate it.
I plan on using Dyson Analysis shortly. I'll have UOAs ran on both 15W40 and 10W30, and see how the numbers compare. If there's a benefit to running 10W30 year round, which I assume would be a tiny bit of an increase in mpg compared to 15W40, I'll strongly consider it. Thanks for sharing your knowledge, I very much appreciate it.
Nah. Nothing in that regard is significantly different in my case. There may be some benefit in terms of mpg by using 10w30, but my primary motivation to go with 10w30 years round is simplicity. I use the oil in a variety of stuff and having one oil that works across the board in my situation just keeps things simple. I really can't advocate that everyone else do the same thing, they have to make up their own minds. You might say, there is no wrong answer.
Interesting.
Wonder how Amsoil's DZF 0w40 does in summer towing & winter cold starts, has an HTHS of 4.2 but still has a CCS viscosity of just 5775 at -35c
https://www.amsoil.com/lit/databulletins/g3467.pdf
Originally Posted by SavagePatch
So... roughly...
15w40 = 4.3
5w40 = 3.8
10w30 = 3.5
FA-4 = 2.9
I've ran consecutively and had UOA's done, for fun, with 0w40, 5w40, and now 15w40 in my Ram EcoDiesel. The UOA's so far have been "boring" (thanks for the new termonology Dnewton). Maybe I'll do a 10w30 next. Not for scientifically definitive data, just for fun.
Wonder how Amsoil's DZF 0w40 does in summer towing & winter cold starts, has an HTHS of 4.2 but still has a CCS viscosity of just 5775 at -35c
https://www.amsoil.com/lit/databulletins/g3467.pdf
Originally Posted by SavagePatch
So... roughly...
15w40 = 4.3
5w40 = 3.8
10w30 = 3.5
FA-4 = 2.9
I've ran consecutively and had UOA's done, for fun, with 0w40, 5w40, and now 15w40 in my Ram EcoDiesel. The UOA's so far have been "boring" (thanks for the new termonology Dnewton). Maybe I'll do a 10w30 next. Not for scientifically definitive data, just for fun.
The ranch I used to work for had a fleet of KW's and Pete's, all with Cummins. All ran SAE 30 HD, period. Cali weather meant no starts below freezing, so that's the way he rolled. Engines had been running since the 1960's (small cam 335 in the old show truck) on for each decade, and all had at least 250,000 with no signs of abnormal wear or bad UOA's. Some had reached 500,000 which is no big deal, but good with aging.
Most over the road diesels love 30. But that's not 10W and a bunch of VII's to to 30 ...
Most over the road diesels love 30. But that's not 10W and a bunch of VII's to to 30 ...
Last edited:
Originally Posted by skyactiv
Don't rely on what your service manager says, rely on your owners manual. Remember, FCA pays for all warranty work and your dealer wont back you
if FCA denies a warranty due to using the wrong viscosity.
^^^ THAT ^^^
( I never can understand why people who buy a product ignore what the maker of the product says to use over the "advice" of someone who has nowhere near the education to give that advice, never mind that fact that he is not the one who designed, engineered and built the product)
Don't rely on what your service manager says, rely on your owners manual. Remember, FCA pays for all warranty work and your dealer wont back you
if FCA denies a warranty due to using the wrong viscosity.
^^^ THAT ^^^
( I never can understand why people who buy a product ignore what the maker of the product says to use over the "advice" of someone who has nowhere near the education to give that advice, never mind that fact that he is not the one who designed, engineered and built the product)
Last edited:
The same reasoning implies one is far better off reading the manufacturer's label on the oil bottle, rather than asking for real world end user input on this forum.
Owner's Manuals indicate pretty broad viscosity ranges, and as long as one keeps within the usage guidelines, I don't think FCA would deny warranty.
Originally Posted by alarmguy
Originally Posted by skyactiv
Don't rely on what your service manager says, rely on your owners manual. Remember, FCA pays for all warranty work and your dealer wont back you
if FCA denies a warranty due to using the wrong viscosity.
^^^ THAT ^^^
( I never can understand why people who buy a product ignore what the maker of the product says to use over the "advice" of someone who has nowhere near the education to give that advice, never mind that fact that he is not the one who designed, engineered and built the product)
Owner's Manuals indicate pretty broad viscosity ranges, and as long as one keeps within the usage guidelines, I don't think FCA would deny warranty.
Originally Posted by alarmguy
Originally Posted by skyactiv
Don't rely on what your service manager says, rely on your owners manual. Remember, FCA pays for all warranty work and your dealer wont back you
if FCA denies a warranty due to using the wrong viscosity.
^^^ THAT ^^^
( I never can understand why people who buy a product ignore what the maker of the product says to use over the "advice" of someone who has nowhere near the education to give that advice, never mind that fact that he is not the one who designed, engineered and built the product)
Originally Posted by alarmguy
( I never can understand why people who buy a product ignore what the maker of the product says to use over the "advice" of someone who has nowhere near the education to give that advice, never mind that fact that he is not the one who designed, engineered and built the product)
These are also the same people who sold an engine and called for a C3 oil, and then found something wanting and went to the scattergun approach of E7, E9 or CJ-4 or newer or A3/B4.
( I never can understand why people who buy a product ignore what the maker of the product says to use over the "advice" of someone who has nowhere near the education to give that advice, never mind that fact that he is not the one who designed, engineered and built the product)
These are also the same people who sold an engine and called for a C3 oil, and then found something wanting and went to the scattergun approach of E7, E9 or CJ-4 or newer or A3/B4.
Originally Posted by ofelas
The same reasoning implies one is far better off reading the manufacturer's label on the oil bottle, rather than asking for real world end user input on this forum.
Owner's Manuals indicate pretty broad viscosity ranges, and as long as one keeps within the usage guidelines, I don't think FCA would deny warranty.
Originally Posted by alarmguy
Originally Posted by skyactiv
Don't rely on what your service manager says, rely on your owners manual. Remember, FCA pays for all warranty work and your dealer wont back you
if FCA denies a warranty due to using the wrong viscosity.
^^^ THAT ^^^
( I never can understand why people who buy a product ignore what the maker of the product says to use over the "advice" of someone who has nowhere near the education to give that advice, never mind that fact that he is not the one who designed, engineered and built the product)
Those educated folk also have to please the EPA.
The same reasoning implies one is far better off reading the manufacturer's label on the oil bottle, rather than asking for real world end user input on this forum.
Owner's Manuals indicate pretty broad viscosity ranges, and as long as one keeps within the usage guidelines, I don't think FCA would deny warranty.
Originally Posted by alarmguy
Originally Posted by skyactiv
Don't rely on what your service manager says, rely on your owners manual. Remember, FCA pays for all warranty work and your dealer wont back you
if FCA denies a warranty due to using the wrong viscosity.
^^^ THAT ^^^
( I never can understand why people who buy a product ignore what the maker of the product says to use over the "advice" of someone who has nowhere near the education to give that advice, never mind that fact that he is not the one who designed, engineered and built the product)
Those educated folk also have to please the EPA.
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