Short Oil Life

[ESchirmer]

I own an 08 2500HD with a 6.6L LMM Diesel with 67,000 miles. During the last two months I have had the oil changed four times or about every 1500 miles. The DIC tells me the oil life remaining is 2% each time. Two weeks ago I had the oil changed and was keeping an eye on the DIC. This weekend it droped from 98% too 86% in just five miles. The dealer changed the Mass Air Flow Sensor last week thinking it might be the problem obvisisley it wasn't. It is back at the dealer today. Has anyone seen this before?

[WhiteTruck]

No, but here are few notes I found to give you somethings to consider.

Oil life monitoring is dependent on vehicle use. Oil life monitoring and change intervals will differ depending on how the vehicle is driven.
Are there any trouble codes? Engine drivability concerns may induce early oil change messages or erratic OLM operation.
Intake or exhaust leaks can affect this and can be tested by completing Charge Air Cooler Diagnosis (Full System Air Leak Test and the Induction System Smoke Test).

During exhaust filter regeneration fuel is injected into the engine cylinders via specifically timed fuel injector pulses (post injections). The fuel flows through the opened exhaust valves, and reacts with the diesel oxidizing converter (DOC). The fuel-rich exhaust gases are converted to heat and start the regeneration event. The higher exhaust temperatures are used to clean the accumulated soot out of the Diesel Particulate Filter (DPF). The regeneration event will result in some amount of fuel-in-oil dilution. The Engine Oil Life System Monitor models the amount of fuel-in-oil dilution between oil changes, and predicts when an oil change is required.

There are four independent DPF regeneration triggers that determine when a cleaning event should begin:
1. Engine run time (includes all idle time as well as driving time).
2. Total measured fuel consumed.
3. Vehicle distance traveled.
4. DPF soot accumulation (as reported by the DPF differential pressure sensors). I suppose a skewed sensor could affect this. What are the soot mass readings after a regen? Before/after sensor readings?

Driving habits? Driving the vehicle at speeds above 30MPH with minimal stops provides the most efficient regeneration (cleaning) of the DPF. It will also lead to maximum oil change intervals. As the vehicle drive cycles fall below 30MPH (with more stops and/or idle time), the regeneration events become extended in duration, and more frequent. These slower speed drive cycles increase the fuel-in-oil dilution, and result in shorter oil life calculations.
There is no repair for early oil change messages or erratic OLM operation, as this is a drive cycle induced condition.

Hope you come up with something.....

[ESchirmer]

Thanks for the input.