Mobil 1 TDT 5W/40, 2007 GMC LMM, 6.5K, 47.4K

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Here's the two oil reports I have done on my new-ish Duramax. The 1st number is the 1st report, the 2nd number is the 2nd report. The last number in parenthesis is the universal average.

Both these OCI's done when the truck said to. Recent change and sample taken good and hot after a full days driving. The engine completed a regen in the morning, then we drove it all day, 150 miles round trip to Mt Rainier. Lots of stops and slow windy roads.

Code:
Oil … Mobil 1 TDT 5W/40, Mobil 1 Oil Filter

Miles in Use … 10,000, 8 Months … 6,5OO, 8 Months

Miles on Unit … 25,500 … 47,400

Sample Taken … 6/10/2009 … 8/17/2011

Make up Oil … 0 … 0



Aluminum ... 3 … 2 … (2)

Chromium … 1 … 1 … (0)

Iron … 23 … 19 … (12)

Copper … 32 … 4 … (10)

Lead … 3 … 3 … (3)

Tin … 2 … 0 … (1)

Molybdenum … 12 … 1 … (29)

Nickel … 0 … 0 … (0)

Manganese … 1 … 0 … (0)

Silver … 0 … 0 … (0)

Titanium … 0 … 0 … (0)

Potassium … 14 … 0 … (3)

Boron … 42 … 42 … (48)

Silicon … 9 … 8 … (9)

Sodium … 13 … 3 … (3)

Calcium … 1116 … 1209 … (2721)

Magnesium … 716 … 781 … (215)

Phosphorus … 839 … 909 … (1092)

Zinc … 1106 … 1003 … (1289)

Barium … 0 … 0 … (0)



Insolubles % … 0.4 … 0.2 … (< 0.6)

Water % … 0 … 0 … (0)

Antifreeze % … 0 … (0)

Fuel % … 1.5 … 4.0 … (< 2.0)

Flashpoint ºF … 395 … 370 … (> 410)

SUS Viscosity @ 210ºF … 66.3 … 68.5 … (65-76)

cSt Viscosity @ 100ºC … 11.96 … 12.56 … (11.6-14.8)

TBN … 4.3 … 5.4


Blackstone's comments:

Quote:
We haven't seen your Duramax in quite some time, but even after almost 24,00 miles this 6.6L looks good in analysis. Wear metals read around universal averages, which are based on ~6,600 miles. Copper improved to a better-than-average reading since your last sample, showing minimal wear at brass/bronze parts. We did note fuel at 4.0% which is a problem reading. It didn't affect wear or the viscosity, but it's still a cautionary level of fuel. The TBN was 5.4, showing lots of additive left. (A TBN of 1.0 is low). Check back to monitor fuel.
 
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Seems good to me, wear metals are trending down, flashpoint and insolubles seem to indicate soot is under control.
Any towing to consider during the run?
 
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The only generation of Dmax that has a potential for leaking injectors to dilute fuel is the LB7 (2001 - 2004) because the injectors were inside the valve covers. All others (LLY, LBZ, LMM, LML) have the redesigned system where the injector is outside the valve cover. The OPs rig does not suffer from the LB7 injector issues; it's a different design.

The LMM is unique in that it has regen events within the engine. The new LML has a ninth injector down near the DPF, so the regen event does not dilute oil with raw fuel.

This UOA is decent as far as wear goes, but fuel is a concern. Keep an eye on it. I'd UOA every 5-6k miles until the fuel issue is satisfactorily known.
 
Only towed once for a couple hundred miles in this run. I always have run B2-B5 BioDiesel if that comes to play on the fuel dilution. Always use Stanadyne PF also.
 
Originally Posted By: Duramax_LMM
Only towed once for a couple hundred miles in this run. I always have run B2-B5 BioDiesel if that comes to play on the fuel dilution. Always use Stanadyne PF also.


Good choice for fuel and additive.
 
Originally Posted By: dnewton3

The LMM is unique in that it has regen events within the engine. The new LML has a ninth injector down near the DPF, so the regen event does not dilute oil with raw fuel.

This UOA is decent as far as wear goes, but fuel is a concern. Keep an eye on it. I'd UOA every 5-6k miles until the fuel issue is satisfactorily known.


Yep, LML has a great design to the emissions system. A lot like the Detriot DD15 and DD13...but I digress. Might just be higher from a lot of regens...you mention a lot of slow driving..that can cause soot to build up in the EGR and incomplete combustion so between those too it could lead to higher fuel amounts in the oil.
 
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