my OLM goes the OTHER way...

[meep]

2008 Jeep GC 3.7l.

I was reading the recent thread of a GM OLM targeting ~11,000 miles, a pretty high OCI.

My jeep goes the other way and I really can't figure out why. Manual says it's condition-based. You can't ask it for a % value, it just one day pops up the message.

I drive conservatively. easy on the gas, anticipate stops, don't follow close. 95% of my driving is beneath 3k rpms, and most of the time when I accelerate, it shifts at 2000 or so.

My commute is 30 minutes each way, and I combine trips. If it's any indication, I average always over 20mpg in this suv.

Manual says follow OLM, max length of oil is 6,000 miles if you ignore OLM.

It always triggers prior to 3,000 miles. Usually around 2400-2500.

What's up with that??

Meep!

 

[d00df00d]

Do you know if your engine has sensors to take direct measurements on the oil (e.g. optical, conductivity), or if it's just a guess based on operating conditions (fuel injected, throttle position, RPMs, etc.)?

Also, is your commute mostly stop-and-go?

 

[tinmanSC]

Originally Posted By: d00df00d
Do you know if your engine has sensors to take direct measurements on the oil (e.g. optical, conductivity), or if it's just a guess based on operating conditions (fuel injected, throttle position, RPMs, etc.)?

Also, is your commute mostly stop-and-go?

Are there any OLMs that sample the oil directly??? I have not heard of any that do this on-vehicle. (On cars, I mean! Not exotic equipment. )

 

[infecto]

Originally Posted By: meep
2008 Jeep GC 3.7l.

I was reading the recent thread of a GM OLM targeting ~11,000 miles, a pretty high OCI.

My jeep goes the other way and I really can't figure out why. Manual says it's condition-based. You can't ask it for a % value, it just one day pops up the message.

I drive conservatively. easy on the gas, anticipate stops, don't follow close. 95% of my driving is beneath 3k rpms, and most of the time when I accelerate, it shifts at 2000 or so.

My commute is 30 minutes each way, and I combine trips. If it's any indication, I average always over 20mpg in this suv.

Manual says follow OLM, max length of oil is 6,000 miles if you ignore OLM.

It always triggers prior to 3,000 miles. Usually around 2400-2500.

What's up with that??

Meep!


Does the 2008 Jeep even have an OLM? I honestly have no idea but if I had to guess I would say it not an OLM and just a static mileage indicator. I would guess you know better though.

 

[oggb]

Unless that engine's a know sludger or something there's absolutely no way I'd change the oil any earlier than 4,000-5,000 miles...

I mean, it can't be THAT hard on oil...

 

[Trav]

Seeing as they were still together with Daimler/Mercedes around this time period (late 2007) i guess its possible they may have still used their FSS (Flexible Service System).

This is a description.
The FSS on some Mercedes vehicles monitors actual oil quality as well as operating conditions (such as the number of cold starts, average engine temp, mileage driven, oil sump level, rpms, etc.). To measure oil quality, there is actually a sensor that measures the electrical conductivity of the oil. The higher the conductivity of the oil, the greater the need for an oil change, according to Mercedes. Of course, this isn't likely a perfect model, and will not be nearly as accurate as an actual oil analysis in determining true oil quality, but it is better than no measurement at all.

 

[gfh77665]

Is it being reset at time of change?

 

[The_Eric]

Just read about this very issue in Motor Magazine. Vehicles affected are built prior to 2/22/2008. It happens most frequently after a battery disconnect but can also happen simply by doing a reset on the monitor. It is due to a software glitch and can be corrected by a reflash.