LMM Duramax 400k mi; Delo 5w-40 20k mi

Messages
5,124
Location
Atlanta,GA
Originally Posted by PiperOne
It's miles...not km. Bought it in the US. To be fair and open...this engine's emission system has been modified. It does return to stock form if it goes to California or other emission hyper locations (about 45 mins to change it back over). About 15% of these miles are with the unit doing regens etc but the rest are more like an LBZ...just EGR and DOC...no DPF. It was ugly oil samples (and fuel mileage) from another LMM that convinced me this unit needed to be modified. Based on those samples I would have used conventional oil and likely 10k mi oil changes...and found other ways to deal with the cold start n go situatuons. I'd have no problem treating the newer DEF Duramax's the same as this one...20k. That all said..still happy with the results and I think it's decent proof the Dmax does not need short "oil is cheap" type service intervals.
No DPF eh? I guess that means no regen cycles either?
 
Messages
62
Location
TX
Originally Posted by PiperOne
I did push one service out to 31,000 miles...just to see..and that sample's values are included in the list above...and it did really well...even out that far. It was summer however..so I backed it back down to 20,000 to make myself feel better about winter and idling and what that can do..and 20k is easy math for my feeble brain! The worst oil sample to come from this truck was a short change interval to get things back on the perfect 20k interval...8000 miles.. it was not as nice as the rest. In an earlier post you mentioned std deviation values..and how you liked 30 samples plus. If it is easy to explain....what is the standard deviation value and what is it's usefullness in these reports?
Can you explain why the 8k oci wasn't as good as the 20k? Just learning here.
 

4WD

Messages
13,567
Location
Texas
Especially with sump drained oil having only reasonable source controls for the sample. By comparison, UOA samples on our industrial engines come from the same sample valve in an oil cooler loop - fixed rate and temperature with engine under load. (they will not accept sump samples).
 

PiperOne

Thread starter
Messages
273
Location
A Highway Near You
Originally Posted by oakaro68
Originally Posted by PiperOne
I did push one service out to 31,000 miles...just to see..and that sample's values are included in the list above...and it did really well...even out that far. It was summer however..so I backed it back down to 20,000 to make myself feel better about winter and idling and what that can do..and 20k is easy math for my feeble brain! The worst oil sample to come from this truck was a short change interval to get things back on the perfect 20k interval...8000 miles.. it was not as nice as the rest. In an earlier post you mentioned std deviation values..and how you liked 30 samples plus. If it is easy to explain....what is the standard deviation value and what is it's usefullness in these reports?
Can you explain why the 8k oci wasn't as good as the 20k? Just learning here.
I really don't have a scientific explanation.....but the short sample was the worst.
 
Messages
62
Location
TX
Originally Posted by kschachn
Originally Posted by oakaro68
so was the whole "that engine is on death's doorstep" a sarcastic comment dnewton3?
Originally Posted by dnewton3
Doing the math; 20 OFCIs at 20k kms each - that's 400k kms (give or take a little). That engine is on death's doorstep, and probably won't last much more than an additional 600K kms! LOL! (I am presuming kms because it's in Canada).
What do you think?
I think I'm not educated enough on the matter to assume my own conclusion, hence the reason I put my pride aside on a public forum and asked. I'm here to learn not try to embarrass those who ask a "dumb question". Question stands.
 
Messages
41
Location
Conroe, TX
Good to see another LMM van still going strong. I have an 09' LMM van that I run oil field service in. Same story, on call 24/7 and need to get out and on the road ASAP. I'm currently at 232,000 miles and a little over 10,000hrs. It spends a lot of time idling. I mostly run Rotella 15/40 with M1 303A filters every 12k miles. I may push it to 15k soon. All the UOAs have come back great with plenty of TBN left. It's fully deleted though. My only worry is how long the 4L85E trans will last. Fingers crossed.
 

dnewton3

Staff member
Messages
8,459
Location
Indianapolis, IN
Originally Posted by NVRENUFF
... My only worry is how long the 4L85E trans will last.
Probably not as long as the Alli 1000, but then again, your LMM isn't tuned for as much torque as the full-on truck version, is it? I thought that the van versions were detuned a bit? OTOH, rebuilding the 4L85E is fairly quick and inexpensive. In fact, when it starts to show the first signs of issues, I'd get a good quality aftermarket reman and just keep on motoring along. Far cheaper than getting a new van.
 

PiperOne

Thread starter
Messages
273
Location
A Highway Near You
Originally Posted by NVRENUFF
My only worry is how long the 4L85E trans will last. Fingers crossed.
Well over 500,000 miles now and transmission is still original. 40k mile service intervals and Chevron full syn Dex6. Oil samples (and what's in the pan) say things are still pretty decent inside...but I am paying pretty close attention because I think these are 500k mile transmissions...even if looked after.
 
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