2024 Chevy Tahoe LM2 3,000 miles/65 hours on oil - 3,000 total miles/65 total hours - HPL 0w-20 Dexos D

wwillson

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Messages
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Location
Colorado
This is the factory oil drained from a 2024 Chevy Tahoe Duramax 3.0L LM2 diesel engine. The factory oil was drained at 3,000 miles. There was no oil consumption despite pulling a small trailer 2,200 miles. I have a Banks iDash which I use to monitor the EGTs and keep sustained EGTs lower than 1,150°F, as to not consume oil engine oil and it works. This engine, similar to the 6.6L Duramax, will consume oil if sustained EGTs are allowed to be higher than 1,150°F. The average EGTs were probably 950-1000°F while pulling. I did not pull the trailer over 70MPH the entire trip and pulled in 8th gear, which is 2,000 RPMs. If allowed the computer will pull the trailer in 10th at 1,600 RPMs and 1,200°F all day long. The peak EGTs I saw were on an uphill onramp with a heavy foot and reached 1,500°F for a few seconds.

The OEM oil was replace with HPL 0w-20 Dexos D, which I asked them to formulate and blend, as they didn't previously have a Dexos D. Thank you @High Performance Lubricants !!

Sample Information
Sample Date5/4/20245/5/2024
Machine Age miles3,0003,050
Oil Age miles3,00050
Makeup oil quarts00
Filter Age miles3,00050
Oil Changedyesno
Filter Changedyesno
BrandOEMHPL
Viscosity0w-20 Dexos DHPL 0w-20 Dexos D
Wear Metals
Iron387
Chromium<1<1
Nickel<1<1
Titanium<1<1
Silver6<1
Aluminum43
Lead<1<1
Copper102
Tin2<1
Vanandium<1<1
Cadmium<1<1
Additives
Boron40106
Barium32
Molybdenum2771
Manganese2<1
Magnesium15876
Calcium17811167
Phosphorus879798
Zinc927821
Contaminants
Silicon10423
Sodium20
Potassium53
Fuel %<1<1.0
GlycolNEGNEG
Soot%0.20.1
Fluid Condition
TBN7.912.54
Viscosity8.28.9
Oxidation11.20(30)

My observations of EGTs and RPMs if I let the computer control the trans is that when the EGTs reach > 1,250°F, the trans will shift to a lower gear. This is different from the 6.6L which will churn away all day at 1,350°F EGTs if you let it. GM seems to have changed the programming on this engine to shift into a lower gear earlier in an attempt to keep the EGTs down and reduce oil consumption.

The factory oil filter is the first factory filter I have ever removed that wasn't grossly over tightened. Nice work GM. The debris in the filter is a bit shocking, metal and sealant mostly. The factory filter was a PF66 and was well constructed, but is really small.

Note the debris in the filter element:






A PPE oil filter went on to replace the GM PF66. The PPE, filter being much larger, has 40% more filter media and is a heavy duty well constructed filter. The PPE filter even has a magnet in the base.





 
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Where do you buy those filters?
 
Happy to see GM still offering a diesel in 1/2 ton segment. I see what you see on that filter & is a fresh reminder to replace the filter on a shorter run to get rid of that debris within early break-in period. I'm going to check out that PPE oil filter site, sounds interesting. Great pics. Any oil change plans on this Tahoe w/that HPL? Just curious, Thanks for sharing.
 
Overall the report looks really good for this 3.0L Duramax. I wish I could justify owning one.

But speaking of EGTs, you mention GM programming it to shift to a lower gear to avoid EGTs above 1250F on the 3.0 but will do 1350F on the 6.6L all the time. I wonder if they are doing that for aftertreatement durability reason vs oil consumption. The SCRoF, combined DPF and SCR converter, on the 3.0 is much closer to the turbo outlet vs the SCR 6.6L, i.e. less time for the EGTs to drop before entering the SCR. SCR efficiency drops off above 500C, peak SCR efficiency is typically around 300-450C. You also need to start thinking about SCR washcoat durability above 650C. With the combined SCR and DPF on the 3.0L they need to better manage temperatures of the SCRoF since it will be experience DPF regeneation temperatures too, which add to the total time at high temperature, i.e. the main way catalyic converters are aged/tested.
 
I recently saw that oil on HPL's website and it did intrigue me. I will have to try it soon. Also I emailed Liam over at PPE about that filter and he stated that the efficiency at 10 microns is 50% and at 20 microns 85%. I would assume that would be better than the ACDelco offering.
 
Great write up @wwillson ! Never heard of PPE, but the filter difference is dramatic. Also, neighbor bought a Suburban with that engine and loves it. I’ve spent a bit of time talking with him about it. If we were in the market for a new truck, I would give that engine serious consideration. Sadly, the Suburban is just too big for my wife, and I have the Tundra, which is a long way from replacement.

The EGT as part of the shift management is an interesting discovery and I am fascinated that EGT management affects oil consumption that much. Is it because of turbo seals?
 
I wonder if they are doing that for aftertreatement durability reason vs oil consumption.
The two go hand in hand, so I believe they are trying to keep oil consumption down by reducing EGTs, which helps keep the metallic oil additives out of the DPF.

The SCRoF, combined DPF and SCR converter, on the 3.0 is much closer to the turbo outlet vs the SCR 6.6L, i.e. less time for the EGTs to drop before entering the SCR.
This is the LM2, which I don't believe has the SCRoF. Correct me if I'm wrong.
 
The EGT as part of the shift management is an interesting discovery and I am fascinated that EGT management affects oil consumption that much. Is it because of turbo seals?
Not the turbo seals, but the piston crowns. If the pistons get hot enough, you will have evaporative oil loss. We have seen that in my 6.6L pulling my trailer.
 
Wow...that vehicle is still under warranty. I would use only oem parts and dealer servicing. You are asking for trouble. Good luck. 😜
The filter is outstanding quality and I've never serviced anything at the dealer. But I did have a kid at a Dodge dealer torque the daylights out of the filter on the Durango and crack the filter housing, when they changed the oil after I told them not to. I do everything I can myself, because I want it done correctly.
 
The filter is outstanding quality and I've never serviced anything at the dealer. But I did have a kid at a Dodge dealer torque the daylights out of the filter on the Durango and crack the filter housing, when they changed the oil after I told them not to. I do everything I can myself, because I want it done correctly.
I was ribbing you Wayne. We have those types here... that filter is a beast.
 
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