When Not to Follow the OLM

[Gene K]

Im having an issue with the OLM in my 2010 Dodge Ram 1500 4x4 4.7L.

1. Typical commute 16 miles in 24 minutes in suburban driving (lots of 40-45 mph speed limits as opposed to lights or traffic) at an average speed of 40 mph.

2. I have averaged 19.3 mpg for the last 8 months. Worst tank was 17.7 mpg in January. The truck is rated for 13 City, 18 Highway and 15 combined.

3. My 2011 5.0L Mustang (OLM is programmed for conventional) on the same commute gets 25-27 mpg and shows 85% Oil Life remaining after 2500 miles.


4.The Dodge Ram OLM does not read in percentages (Its a simple change oil soon message ) and comes on 500 miles before an oil change is required. It is illuminating after 2500 miles for a maximum 3000 mile oil change and has done so 3 of the last 4 times.

Anyone think it might be just a wee bit conservative?

Im going to run a UOA this time and see what it looks like but if it comes back looking like I expect Im tempted to just ignore it in the future.

 

[dave1251]

Is the OLM in your Ram a true OLM or is it an "not so smart person oil change reminder". If it a true OLM or not I would take it back to the dealer if you are under warranty and have it checked. If not I would say even a 7K OCI is a conservative OCI.

 

[Gene K]

Its a True OLM but Chrysler Corp chose to limit it to a maximum of 6000 miles in 2010 and 8000 miles in 2011. Its like the system in the cheaper GM Cars were you can not see a percentage readout.

Im thinking I may be doing something that causes the system to deduct mileage. For instance I turn the truck off when Im going to be idling over 30 seconds and these extra starts may be counting off (even though the idle would be worse). Its also possible the slow average speed of my commute is being counted like it was stop and go driving with the same average speed rather than constant low load driving.

Asking for an oil change after only 129 gallons of fuel with a 6 quart oil capacity just seems silly.

 

[dave1251]

I agree that is very silly if I changed at that rate that would be like 2 months of usage more or less.

 

[Gene K]

The parameters used to calculate my Oil Change Due Message:

1. Ambient temperature – extended periods of low temperature operation
2. Average vehicle speed – stop and go driving
3. Engine run time – prolonged idling
4. Trip length and coolant temperatures – short trips
5. Engine speed and load – trailer tow usage
6. Flex-fuel percentage – ethanol percentage of more than 60%

Based on this information, at a fixed number of miles since the last reset of the system, the PCM calculates the combined effects of these variables to determine if a severe usage pattern exists. If severe usage is determined, the oil change message is activated at 2,500 miles; otherwise, the message is not displayed until additional mileage has accumulated.

Conclusion
Im thinking is its a combo of:
1.My low average speed (Which its considering stop and go driving).
2. Shutting the engine off whenever I believe it will idle over 30 seconds (Which it is counting as separate trips thus shortening average trip length).

 

[trooper001]

Originally Posted By: Gene K

2. Shutting the engine off whenever I believe it will idle over 30 seconds (Which it is counting as separate trips thus shortening average trip length).


This is the correct answer on why your OLM is flagging you down to change the oil earlier than necessary. Perhaps you should try not shutting down the engine at stops on the next OCI and see how far it goes. I bet it goes beyond 3,000 miles easily.

 

[08_SHELBY]

The OLM on my work chevy truck says 20% life left @ 6000 miles. mostly highway and country driving.

 

[SteveSRT8]

You cannot compare the relatively recently developed Chrysler OLM to the GM OLM. GM makes a superior system that is proven in everything except DI applications. Extremely accurate and responsive.

I have had GM OLM's in our fleet go off as low as 4400 miles in our work vans and as high as 14k miles in my Silverado. When they first came to us in 04 we used oil analysis for two years making sure, this system is accurate. This is despite the fact there is no readout available to the driver at all.

 

[MuzzleFlash40]

The OLM in my Mercury is just a mileage counter, every 5k. The OLM in the impala went off at 7,800 with 10 miles one way work trips 5 days a week and 90 mile round trip highway trips on the weekends. I just follow the OLM on both cars now, lol