Anyone know how the oil life monitor works and how accurate it is?
 

I've never had a car with one of these. Oil change clocks yes, but a sensor system no. How does it work? An engineer friend suggested it measures electrical resistance in the oil. That seems plausible as metal particles and other contaminants build up in the oil. Does anyone know how it actually works? Can it be trusted? My 12 GT is 2 months old, has 1700 miles and still has 85% oil life?

I don't know for sure, but I say its set up on a time/mileage basis. I can almost guarantee its not measuring anything in the oil itself. Mine gauges said "oil change required" at precisely 6 months, even though it had only been 2000 miles. I've seen other people post that theirs went off at 6 mo. and only had a couple hundred miles. I'm of the opinion that it goes off at 6 mo. or 7500 miles, whichever comes first.

I wouldn't really focus on the percentage...
I go 3,000-4,000 between oil changes, and then reset it....

That's old school man

It probably works off the amount engine load & miles driven

Same here. I don't believe in 5-10k oil change intervals. Oil breaks down and gets contaminated.

Here you go, from the Ford site:

More than likely, if you stayed on top of your required maintenance duties, you’ve changed your oil every 3,000 or 5,000 miles. With the introduction of the IOLM, now you’ll be able to take your vehicle in for an oil change based on actual operating conditions.
What the IOLM measures to determine when an oil change is needed

Several key factors that affect oil life include:

Driving habits (such as towing and workload)
Hours in operation and at idle
Oil and coolant temperature
Engine speed and torque
Diesel particulate filter (DPF) cleaning cycles
How the IOLM works

The IOLM does not use oil quality sensors – it is entirely software-based and uses actual engine operating conditions to calculate the oil change interval by using an algorithm. This means the system must be reset after an oil change. Not doing so will result in a premature OIL CHANGE REQUIRED message.

The frequency of oil changes

Depending on driving conditions, oil change intervals are approximately:

Up to 10,000 miles - Normal commuting with highway driving
5,000 – 7,500 miles - Trailer tow/high-load driving
3,000 – 5,000 miles - Short trip usage, extreme cold or hot temperature
NOTE: Actual mileage will depend on your specific driving conditions.

Under normal conditions, you will get an OIL CHANGE REQUIRED message at up to 1 year, or 10,000 miles from the previous oil change.

What the IOLM tells you

You’ll find a display in your instrument cluster’s message center that will notify you of oil change intervals by displaying ENGINE OIL CHANGE SOON or OIL CHANGE REQUIRED. The system will also indicate when fuel filters need maintenance, or if fuel pressure is low.*

*Refer to owner’s guide for specific applications.

Synthetic oil and the IOLM

Ford engines have been tested using Motorcraft® Synthetic Blended Oils. If you do use synthetic oil, it needs to meet the Ford specifications for motor oil and the specific oil weight as indicated in the owner’s guide. Ford still recommends using the oil change service intervals as indicated by the IOLM.

Vehicles that will get the IOLM

The IOLM will be available on most vehicles under 8,500 lbs. gross vehicle weight rating (GVWR) and the all-new 2011 model year 6.7L Power Stroke® Diesel on the Super Duty® model. That translates into over 90 percent of the 2011 model year Ford, Lincoln and Mercury vehicles sold.

For in-depth details about the IOLM, please refer to your owner’s guide and diesel supplement.

Motorcraft® is a registered trademark of Ford Motor Company.

Thanks for this. Ok,a software algorithm. Not what I thought, kind of a more sophisticated clock I suppose.

Yeah - 3-4k is stupid under most conditions. Plus they are not thinking of the larger capacity of the 5.0 - which takes longer for contaminents to affect the overall condition of the oil.

I am thinking about the longevity of the motor. Fresh oil can't do anything but be good for the motor, can't hurt. Nothing stupid about that IMO...

that kind of thinking.. change the clutch while you are at it.

FYI -

1990s vintage video, but still true I guess.