Mobil Delvac ESP 5w-40, 6.6k mi; 2024 Ram 2500 6.7 Cummins 16.5k mi

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May 14, 2023
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Pennsylvania
Looking for thoughts/opinions regarding this UOA. This is the third UOA I’ve done on the truck since new. I’ve changed the oil at 3k, 9k, and 16k miles. I was hoping to see potassium starting to trend down, but that is not the case. Also, iron is now 118 and was previously 47. Copper went from 31 to 90. I have not used any fuel additives; however, I did use Power Service Extreme Diesel, which is a collaboration with some fuel stations; in this case, it was a Sinclair station. I quit using it and went back to primarily Marathon Diesel as I noted more frequent regens using the other fuel (coincidence? maybe, but I quit using it last time because of the same issue). Prior to this oil change, I noticed an erratic tick on the passenger side of the engine; I don’t think it’s lifters as it’s erratic and sounds more like a manifold leak, but it’s not. Diesel tech said normal EGR function 🙄 when I took it in. This truck is daily driven and sees a mix of highway and stop-and-go. I don’t have any frequent regens issues, and it sees enough highway to passively regen. This oil was run all winter in -8F temps, so there may have been slightly more idle time than summer; but nothing excessive. I can post previous UOAs if anyone would like to see/compare.

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First, I'd ask them to rerun the sample and confirm the data.

Observations on the current state:
- Fe is high and apparently on the rise. If this were break-in metals, it should be going down, not up.
- 4% fuel is a lot for a new engine; perhaps some of it is idle at cold temps, but that should have burned off by now if it was only winter related
- the Cu is on the rise, per your data. Again, break-in metals should go down, not up.
- K is high
- physical contamination (soot; Si) are low, so they are not an issue

It's not time to panic, but it's time to collect more data and have cautious concerns. Run another 5k miles and see where things go.

What type of oil cooler does this engine have? What's it made of (metals wise)?
 
First, I'd ask them to rerun the sample and confirm the data.

Observations on the current state:
- Fe is high and apparently on the rise. If this were break-in metals, it should be going down, not up.
- 4% fuel is a lot for a new engine; perhaps some of it is idle at cold temps, but that should have burned off by now if it was only winter related
- the Cu is on the rise, per your data. Again, break-in metals should go down, not up.
- K is high
- physical contamination (soot; Si) are low, so they are not an issue

It's not time to panic, but it's time to collect more data and have cautious concerns. Run another 5k miles and see where things go.

What type of oil cooler does this engine have? What's it made of (metals wise)?
Yeah, I felt as though some wear metals were trending in the wrong direction. I believe the oil cooler is made of aluminum, and it’s a liquid-to-liquid design. Thanks for the input; I appreciate it; I’m slightly concerned.
 
I'd need some kind of explanation on where the potassium is coming from after 17k miles That combined with the high wear numbers(increasing) seems to indicate an issue.

Diesel in oil evaporates relatively slowly 4% over a winter oci does not seem to rise to the level of indicating a problem.
 
A change in brand of oil and additive chemistry will often cause copper to spike from the oil cooler.
Cold winter starts and short trips are hard on oil. The viscosity @ 100C is almost a 30 grade.
Obviously you didn’t buy the truck to test engine oils, or experiment with extended drain intervals to save money.
Instead, try a couple thousand fewer miles between drains in the winter.
 
A change in brand of oil and additive chemistry will often cause copper to spike from the oil cooler.
Cold winter starts and short trips are hard on oil. The viscosity @ 100C is almost a 30 grade.
Obviously you didn’t buy the truck to test engine oils, or experiment with extended drain intervals to save money.
Instead, try a couple thousand fewer miles between drains in the winter.
Kv100 only starts at 13.8 for the Delvac. Given the 4% fuel dilution, I’d expect the viscosity to decrease and result about where it currently resides. I ran VPBE 5w40 prior to this, and I’m currently running Delo XSP 5w40. I don’t short-trip it, per se, as my daily commute is about 40+ miles with a majority highway and some city. I also drive a fair amount of highway on the weekends; just turned about 375 miles today. The last OCI fuel dilution was less than 2% with almost the same OCI length. The main factor I believe is the erratic tick that started mid-January of this year, but like I said, I’m open to hearing any and all input. I will say that since I switched to Delo, the soot loading, as monitored by my Scangauge, has decreased, and the engine is much quieter; despite the tick, which remains. If I were a betting man, I’d say this truck has some sort of internal issue. I don’t even tow with it; yet, and may never at this point.
 
Kv100 only starts at 13.8 for the Delvac. Given the 4% fuel dilution, I’d expect the viscosity to decrease and result about where it currently resides. I ran VPBE 5w40 prior to this, and I’m currently running Delo XSP 5w40. I don’t short-trip it, per se, as my daily commute is about 40+ miles with a majority highway and some city. I also drive a fair amount of highway on the weekends; just turned about 375 miles today. The last OCI fuel dilution was less than 2% with almost the same OCI length. The main factor I believe is the erratic tick that started mid-January of this year, but like I said, I’m open to hearing any and all input. I will say that since I switched to Delo, the soot loading, as monitored by my Scangauge, has decreased, and the engine is much quieter; despite the tick, which remains. If I were a betting man, I’d say this truck has some sort of internal issue. I don’t even tow with it; yet, and may never at this point.
Did Cummins go back to mechanical lifters on the 6.7, or are they still the ill fated hydraulic ones?
Nevertheless Delo 5w40 starts out around 15.5@100C, making it one of the thicker 5w40s.
With that you’re changing additive chemistry again, this time from Infinium to Oronite which might spike the copper again.
 
Did Cummins go back to mechanical lifters on the 6.7, or are they still the ill fated hydraulic ones?
Nevertheless Delo 5w40 starts out around 15.5@100C, making it one of the thicker 5w40s.
With that you’re changing additive chemistry again, this time from Infinium to Oronite which might spike the copper again.
Still hydraulic unfortunately
 
I would keep an eye on things. My Cummins took several thousand miles (~35k) to settle in and drop the iron out of the UOA's. I have an older 2012, but it had a new short block when I bought it in 2016. I started with Mobil Delvac 5w-40 but it was shearing so I switched to 15w-40. Obviously that is not recommended for your engine with the lifter set up.

The ticking is a complaint that I have heard. It seems they blame the EGR or the turbo actuator. Apparently neither are an issue, but it is annoying.

A couple of my UOA's for reference
 
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