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Re: 10w30 vs. 15w40: Is there a difference? [Re: ammolab] #4928031
11/18/18 06:48 PM
11/18/18 06:48 PM
Joined: Jan 2018
Posts: 272
Missouri
BigShug681 Offline
BigShug681  Offline

Joined: Jan 2018
Posts: 272
Missouri
Originally Posted by ammolab
Same oil: 10W-30 is US measures while 15W-40 is Metric

That is why an American Honda manual can call for 5W-20 while the Russian manual lists 5W-40.

😏

Wait, what?


2006 F350 DRW 6.0 PSD with a ZF6 6Speed. If you can't find it or float it then just grind it
Re: 10w30 vs. 15w40: Is there a difference? [Re: dlundblad] #4928544
11/19/18 07:44 AM
11/19/18 07:44 AM
Joined: May 2007
Posts: 7,810
Indianapolis, IN
dnewton3 Offline
Global Moderator
dnewton3  Offline
Global Moderator

Joined: May 2007
Posts: 7,810
Indianapolis, IN
OP -

I will say this ... in terms of what's in the bottle, certainly there is a difference, as you inquire.
But as for results, there's rarely any distinction between the two. Wear data will not show any significant difference in just about any application.


The act of preventative maintenance, in and of itself, is FAR MORE important than brand/grade/base choices among lubes and filters.
- under maintaining something is akin to abuse/neglect; that can kill equipment by shortening the lifespan
- over maintaining something has never been proven to be anything but a waste of time and money
Re: 10w30 vs. 15w40: Is there a difference? [Re: dlundblad] #4933486
11/23/18 11:00 PM
11/23/18 11:00 PM
Joined: Oct 2018
Posts: 1
Northern Territory
SRJ73 Offline
SRJ73  Offline

Joined: Oct 2018
Posts: 1
Northern Territory
My engine is a 4JJ1, in an Isuzu D-Max 4wd.

Factory oil is Besco Duramax 10w-30.

Other recommendations in the handbook are all 15w-40: Shell Rimula R3X, or R2 Extra or R2; Exxon Delvac MX; Caltex Delo 400 or Gold. And a few others listed.

I ran the factory 10w-30 oil for for about the first 2 years of ownership, and a DIY change of the oil every 10,000km.

Have had a Provent oil catch can fitted since day one, and would regularly drain approx 90mm of oil each change.

My local dealer stopped being an Isuzu franchise, and thus I lost access to the Besco oil.

So I changed to Delo 400, and have been using that since, so that's about another 2 years using Delo 400.

The Provent now captures approx 75mm of oil each time.

That's the only noticeable difference I have between using 10w-30 and 15w-40. The D-Max otherwise drives the same, the engine sounds the same and fuel usage is the same between the grades.

[Linked Image]

Re: 10w30 vs. 15w40: Is there a difference? [Re: KCJeep] #4948149
12/10/18 11:44 AM
12/10/18 11:44 AM
Joined: Feb 2012
Posts: 19
WNY
daved5150 Offline
daved5150  Offline

Joined: Feb 2012
Posts: 19
WNY
Originally Posted by KCJeep
My Jeep spec'd 10w30 and would run well on it, from the thinner mainstream stuff to Rotella. Jump to a 10w40 and I would have engine knock at start up unless swapped in 1 quart of 5w20 (out of the 6). I tried to run straight 15w40 once and it knocked no matter what, I had to drain it. Yes there is a difference.


Same for my son's 1999 Cherokee XJ with the I6; it specs 10w30. It gets 5w30.


2016 F350 Lariat CC/SB 6.7PSD 3.55s FS2500 iDash
Re: 10w30 vs. 15w40: Is there a difference? [Re: dlundblad] #4948186
12/10/18 12:42 PM
12/10/18 12:42 PM
Joined: Oct 2015
Posts: 2,930
Balearic Islands , Spain
FordCapriDriver Offline
FordCapriDriver  Offline

Joined: Oct 2015
Posts: 2,930
Balearic Islands , Spain
I prefer sunflower oil


1975 Ford Capri II Ghia 3000 V6, - Shell Helix HX3 20W-50 w/ 20% Rimula R4X 15W-40 HDEO.
1988 Ford Escort XR3i Cabrio, - Shell Rimula R4X 15W-40, w/ 30% Helix 3 20W-50.


Re: 10w30 vs. 15w40: Is there a difference? [Re: dlundblad] #4961379
12/25/18 08:09 PM
12/25/18 08:09 PM
Joined: Aug 2010
Posts: 1,409
pa
benjy Offline
benjy  Offline

Joined: Aug 2010
Posts: 1,409
pa
many specs allow variations for temperature + driving style. those in very cold areas will benefit from thinner oils especially at start up, hot areas just the opposite + overly worn engines will likely do better on thicker 2nd # the hot viscosity which may help consumption. i had a bought new poorly built 72 307 chev motor that was consuming- not leaking a qt in 500 miles by 75 thou!! the 20-50 conventional i resorted to helped until winter came, it WOULD NOT start then!!!!

Re: 10w30 vs. 15w40: Is there a difference? [Re: dnewton3] #4970904
01/05/19 09:47 PM
01/05/19 09:47 PM
Joined: May 2010
Posts: 184
UT. USA
Dak27 Offline
Dak27  Offline

Joined: May 2010
Posts: 184
UT. USA
Originally Posted by dnewton3
OP -But as for results, there's rarely any distinction between the two. Wear data will not show any significant difference in just about any application.


Judging by the UOAs I've had ran on Delvac Super 1300 and Delo 400 SDE 15W40 and Delo 400 XLE and Delvac Elite 10W30, you're 100% correct when it comes to my Detroit Series 60.

I personally use 10W30 in the winter and 15W40 for the rest of the year. My motor definitely turns over easier in the winter using 10W30.


I believe Tired Trucker runs 10W30 year round in his Detroit, and he's stated the 10W30 shears less in his motor. Dusty uses 10W30 year round also, and as you've already stated, his UOA looked impressive to say the least.

I've noticed slightly lower oil temperatures using 15W40 in the hotter months. Not a huge difference compared to 10W30, but enough that I'd rather use the 15W40 when the ambient temperatures get past 85F. To steal a line Tired Trucker, it helps my paranoia gland when my oil temperature is lower. smile

Re: 10w30 vs. 15w40: Is there a difference? [Re: Dak27] #4971093
01/06/19 06:43 AM
01/06/19 06:43 AM
Joined: May 2007
Posts: 7,810
Indianapolis, IN
dnewton3 Offline
Global Moderator
dnewton3  Offline
Global Moderator

Joined: May 2007
Posts: 7,810
Indianapolis, IN
Originally Posted by Dak27
Originally Posted by dnewton3
OP -But as for results, there's rarely any distinction between the two. Wear data will not show any significant difference in just about any application.


Judging by the UOAs I've had ran on Delvac Super 1300 and Delo 400 SDE 15W40 and Delo 400 XLE and Delvac Elite 10W30, you're 100% correct when it comes to my Detroit Series 60.

I personally use 10W30 in the winter and 15W40 for the rest of the year. My motor definitely turns over easier in the winter using 10W30.


I believe Tired Trucker runs 10W30 year round in his Detroit, and he's stated the 10W30 shears less in his motor. Dusty uses 10W30 year round also, and as you've already stated, his UOA looked impressive to say the least.

I've noticed slightly lower oil temperatures using 15W40 in the hotter months. Not a huge difference compared to 10W30, but enough that I'd rather use the 15W40 when the ambient temperatures get past 85F. To steal a line Tired Trucker, it helps my paranoia gland when my oil temperature is lower. smile

Nothing wrong with using a 15w-40 in summer. But as you can already see, whereas using the 15w-40 will reduce temps, it does not necessarily reduce wear.
The point? There's no correlation between wear and the moderate temp shift. Admittedly large temp shifts would be something to concern yourself with, but I seriously doubt that's what we're talking about here.
And out of curiosity, are you speaking of the oil temp, or overall engine temp?

Large grade shifts can certainly be a cause for concern as they might induce a wear shift. Much of this is situation dependent.
Going from a 5w-20 to a 20w-50 in winter in your gasser might be a problem for both starting and wear.
Going to a 5w-20 where a 10w-40 is spec'd in low-pressure (low boundary film layer) application might also be an issue.
- There are examples such as the Ford 4.6L and 5.4L engines running anything from 5w-20 to 10w-40, and they seem immune to wear changes.
- Other examples can be seen; some extreme grade changes induce wear; there's a UOA here from a Dmax diesel that used 15w-40, plus adding Lucas oil stabilizer, and then a non-standard oil filter with no bypass relief; this combination of super thick oil and odd filter has driven up the Al in wear metals.
- Other Dmax examples have shown that in "normal" choice selections, the difference between 15w-40 and 10w-30 are totally moot.
My point is that there are times when grade will matter, and other times it won't. If you cause a LARGE variation in grade, it might affect wear. But generally, going up or down only one grade amounts to no change in wear rates whatsoever. Using a 5w instead of 10w? Not really going to make much difference. Using a 30 grade instead of 40 grade, or 30 grade instead of 20 grade? Moving up or down one grade really doesn't make a hoot of difference in wear control.

The real exception to this is in your cold start capabilities. If you're right on the feathery edge of being able to crank over, then dropping a grade will help out quite a bit. But we're talking about -20F and lower; not "gosh .... it's going to drop down to 43F tomorrow morning, I'd better start using my 0w-20 PAO or my engine will lock up ...."

A grade shift up/down just one category generally has shown no statistical significance in wear control in more than 15,000 UOAs I've looked at.

If the grade shift induces a temp shift, and that temp you're concerned about is on the feathery edge of acceptable, then that might be the reason to use a different grade. Say you were within a few degrees of the temp causing a cooling fan to engage, then choosing the lube that reduces temps would have the effect of improving fuel economy, because when the fan does not come on, or would come on less often (regardless if it's directly or indirectly driven fan), then the net result is less fuel consumed to provide the power to that fan above the power required to move the vehicle. But if the temps are well in control, again, it does not make a difference because it would not change the general operation of the temp controlled condition.

Last edited by dnewton3; 01/06/19 07:00 AM.

The act of preventative maintenance, in and of itself, is FAR MORE important than brand/grade/base choices among lubes and filters.
- under maintaining something is akin to abuse/neglect; that can kill equipment by shortening the lifespan
- over maintaining something has never been proven to be anything but a waste of time and money
Re: 10w30 vs. 15w40: Is there a difference? [Re: dnewton3] #4971644
01/06/19 07:23 PM
01/06/19 07:23 PM
Joined: May 2010
Posts: 184
UT. USA
Dak27 Offline
Dak27  Offline

Joined: May 2010
Posts: 184
UT. USA
Thank you, Dnewton! The difference in temperature is both coolant temperature and oil temperature, but it isn't anything drastic overall. As a matter of fact, I had a switch installed in my truck so I can turn my engine fan on manually. I'm on my second run of Guardol ECT 10W30, and I left with a load of potatoes from Rigby, ID with a gross vehicle weight of just over 79,000 lbs. The ambient temperature at the Shipper was 9F. I saw -11F in Wyoming on US30 on my way heading east. I'm on my way down South, and today in Mississippi I've seen roughly 65F for the ambient temperature. Quite the swing! My coolant and oil temperatures seem pretty par with 15W40 at +65, it's only when it's really hot outside before I see a difference, and I don't think it varies more than +10 degrees running 10W30 vs 15W40 in really hot weather. Really nothing to be concerned about in my opinion.

I'm still on the fence about running 10W30 year round, old habits die hard, they say.

The gentleman who I operate under does a monthly IFTA report, and over the past few months, my MPG average is better than 1 MPG compared to the other Owner Operators here. And that was before I switched over to 10W30 for the Winter. My average using 15W40 over the past 2 months was 6.4 mpg, averaging roughly 66 mph. And a typical mileage week for me is 3500 miles. Sometimes close to 4000 miles in the 70 hours that I'm allowed to run.

I track my MPG religiously, and it has gone up since I switched to 10W30. In over the 2000 miles I just drove, I'm averaging over 6.9 mpg, and that's pulling a few mountain grades in Idaho and across Wyoming, 79,000 lbs gross, before I got to flatter terrain. And my mph average thus far is 66 mph. I typically run 70 mph, which puts my tach in the sweet spot for my motor, right under 1500 rpm.

I'm getting close to turning 400,000 miles on my odometer, and overall this motor has been great. I run it pretty hard. I've had to replace an AC compressor, a turbo, and an alternator, but parts for my Series 60 are pretty affordable, compared to parts for the newer generation EPA motors. I don't run a UOA at every PM, but I do one about every 3 PMs, and all the readings are well within range. I am a little OCD about my PMs, though. I typically have a PM service done every 12,000 to 15,000 miles -during my home time. I stay out a month at a time, and once I start running, there isn't very much downtime to speak of.

As always, thanks for sharing your knowledge, and sorry about such a long post from my end.

Regards, Dak.

Re: 10w30 vs. 15w40: Is there a difference? [Re: dlundblad] #4974820
01/10/19 07:22 AM
01/10/19 07:22 AM
Joined: Sep 2006
Posts: 1,469
Wisconsin
Black_Thunder Offline
Black_Thunder  Offline

Joined: Sep 2006
Posts: 1,469
Wisconsin
Where I work they went from 15w40 to 5w40 synthetic for several years. Then back to 15w40 then to 10w30 synblend and they use that in everything now year round and have pushed the intervals out to 50 to 60k depending on the engines and they do a lot of oil sampling. Most of the trucks have DD15's or the Cummins ISX and some stray older mercedes or 60 series engines and the god awful Maxxpower engine.

Last edited by Black_Thunder; 01/10/19 07:23 AM.

I'd buy Callahan autoparts if I could.
Re: 10w30 vs. 15w40: Is there a difference? [Re: Black_Thunder] #4975378
01/10/19 06:36 PM
01/10/19 06:36 PM
Joined: May 2010
Posts: 184
UT. USA
Dak27 Offline
Dak27  Offline

Joined: May 2010
Posts: 184
UT. USA
Originally Posted by Black_Thunder
Where I work they went from 15w40 to 5w40 synthetic for several years. Then back to 15w40 then to 10w30 synblend and they use that in everything now year round and have pushed the intervals out to 50 to 60k depending on the engines and they do a lot of oil sampling. Most of the trucks have DD15's or the Cummins ISX and some stray older mercedes or 60 series engines and the god awful Maxxpower engine.


If you don't mind me asking, what are their OCIs on the Series 60 motors?

I once drove Company hauling reefer freight Coast to Coast, in a Freight-Shaker with a 14.1L Series 60. I loved that truck! The company I drove for did their OCIs every 35,000 miles, and they used 15W40 Rotella. I'm telling you, that truck gave me zero mechanical problems in the year I drove for them. I believe it had 450,000 miles on the odometer when I first got in it. That truck made me a believer in the Series 60 motor.

I have a friend who's a Company Driver, hauling reefer freight. He runs mostly up on I-80 from the Rockies out to the East Coast and back. They had been running Delo 15W40 for decades, in the past few years they switched their entire fleet over to Delo 10W30 semi-synthetic. IIRC he told me they've now pushed their OCIs out to 70,000 miles from 50,000 miles. Pretty impressive IMO. I believe their entire fleet is now powered by DD15's.

I remember the first time I was told the OCI that Detroit set on the DD15 was 50,000 miles, I thought: "Are they nuts?!?" In my opinion the DD15 is an impressive motor.

Re: 10w30 vs. 15w40: Is there a difference? [Re: dlundblad] #4975703
01/11/19 01:38 AM
01/11/19 01:38 AM
Joined: Sep 2006
Posts: 1,469
Wisconsin
Black_Thunder Offline
Black_Thunder  Offline

Joined: Sep 2006
Posts: 1,469
Wisconsin
We dont have any 60 series left in otr but some day cabs which they do hourly or yearly but when they did they were around 40,000 mile intervals


I'd buy Callahan autoparts if I could.
Re: 10w30 vs. 15w40: Is there a difference? [Re: dlundblad] #4976650
01/12/19 02:07 AM
01/12/19 02:07 AM
Joined: Jan 2008
Posts: 3,397
Central Iowa
TiredTrucker Offline
TiredTrucker  Offline

Joined: Jan 2008
Posts: 3,397
Central Iowa
My 60 12.7 pre-EGR, I have the OCI's at 22,500 mile / 450 hrs. I started at the 15K mile / 300 hr Detroit recommendation and after the initial 3 oil changes, I worked things up. when I went beyond 22,500 / 450, I started noticing a more accelerated up tick in wear metals and such. I backed off and things settled down. Tried one more time and the same result. So I settled in on 22,500 / 450 hrs. Currently 926,000 miles on this factory reman motor. No major repairs, still original turbo and injectors. Only thing that has been done is top end adjustments occasionally. Truck has consistently produced roughly 7.5 MPG average over its life. I typically run 62 mph (1400 RPM) to 66 mph (1500 RPM).

While the oil technically is still good and can go further, based on the trend lines in the samples it seemed that after 450 hrs on the oil, there was a "food fight" starting between the motor and the oil. Wear metal trend lines became more accelerated after 450 hrs. Nitration also was more accelerated. No substantive change in soot or viscosity. 22,500 miles / 450 hrs seem to be the optimal time frame.

But hey, 22,500 miles / 450 hrs is 50% longer drain interval than Detroit recommends on my motor. Oh... using Schaeffer 10w30 711. CJ-4 version early on, CK-4 version for last two years.


Freedom is not about having the choice to do what you want, but the choice to do what you ought.
Re: 10w30 vs. 15w40: Is there a difference? [Re: TiredTrucker] #4976722
01/12/19 07:34 AM
01/12/19 07:34 AM
Joined: Sep 2013
Posts: 10,899
Indiana
dlundblad Online happy OP
dlundblad  Online Happy OP

Joined: Sep 2013
Posts: 10,899
Indiana
Nice to see you back posting.

Thanks for the info.


03 Jeep WJ 4.0 202k Edge 10w40 HM Fram XG16
02 Volvo S60 2.4T 186k M1 0w40 Mahle OX149D
97 Chevy Blazer 4.3 153k Synpower 5w30 Supertech ST3980 (Ecore)

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