My GM OLM Is Wacked Out

Messages
133
Location
Gainesville, Georgia
My work van is a 2004 Express. 5.3 engine. I have it pretty well loaded down. I drive about 50/50 city highway driving. I use the tow/haul mode quite often. On the highway I run about 70 to 80 mph. I let it idle for a good 10 minutes on cold mornings. I defently do not baby this engine in anyway. My OLM has not come on after 9k miles. What in gods name do you have to do to get this thing to come on at 5k miles. I have not gone 9k miles since I last changed the oil. I just didnt reset it to see how far it will go.
 
Messages
7,409
Location
Austin, TX
How many quarts to change the oil and filter? Does the engine have an oil cooler? Do a UOA if you really believe the OLM is whacked.
 
Messages
40
Location
Arkansas
My Duramax OLM did come on after 10,500 miles with the monitor showing 5% oil life left. It does the OCI by engine hourse I believe
 
Messages
1,043
Location
Central IN
There's a lot more to the equation than just engine hours. I don't have the thread handy, but somebody posted the true equation on how the GM OLM works.
 
Messages
1,251
Location
Akron, OH
It's more like it tallies up so many seconds of the engine being on, but if you're driving on a cold engine or in heavy traffic it will count each second as more than one second.
 
Messages
188
Location
QCA, IA
My GM OLM still hasn't come on since I reset it at ~22,500 mi. I'm now just about to hit 60,000 mi. I only have a dummy light so I can't see the percentage left.
 
Messages
783
Location
Austin Texas
The OLM takes into consideration:: A) engine temperature, B) number starts and temperature at startup, C) the RPMs that the engine runs at, D) the throttle openg the engine runs at; to determine when the oil has reached the end of its life. As evidenced, there are cars that are getting 20K+ miles on an OLM indicated OCI and I have seen a car get only 1,000 miles (790 actually = 4% left) on an OLM indicated OCI at a two day drivers education event on a race track in central texas in 103dF heat.
 
Messages
189
Location
Atlanta
If I had an OLM, it would probably come on at every fill up. j/k Too bad there isn't a system that actually analyses the oil for viscocity and remaining additives. Consider two identical vehicles driven in identical manners that had different types of oil. Left say one had M1EP and the other had a no name SL motor oil. I'm sure the M1EP would do just fine while the no name SL would probably look like tar.
 
Messages
50
Location
Saskatchewan
quote:
My GM OLM still hasn't come on since I reset it at ~22,500 mi. I'm now just about to hit 60,000 mi. I only have a dummy light so I can't see the percentage left.
Am I correct in that you've gone nearly 40,000 mi???
 
Messages
188
Location
QCA, IA
You are correct that I've gone nearly 40,000 mi, but not without changing my oil, just since resetting the OLM. My point is that you still have to use common sense.
 
Messages
4,844
Location
Saskatchewan
quote:
My point is that you still have to use common sense.
That's just "old school" thinking. You should do what the computer tells you. [Wink] Sounds like the GM OLMs can't necessarily be trusted. The Duramax OLM coming on at 10,500mi probably makes sense though since they likely have a large sump capacity and longer drain interval.
 
Messages
1,779
Location
Central Iowa
quote:
You are correct that I've gone nearly 40,000 mi, but not without changing my oil, just since resetting the OLM. My point is that you still have to use common sense.
I wonder what would happen if someone had a faulty OLM and went 30-40K on dino with resulting engine damage. Would warranty cover it since the OLM never came on? (just playing the what-if game). And that common sense thing seems to be a rare commodity!
 
Messages
204
Location
River Falls, WI
..actually, the GM OLM is measured by engine revolutions and would care to go into it if you want...but know that you can go 9K miles. It is tailored to your specific engine, driving habits, fuel delivery, engine load, speed as there are certain predictible patterns that oil degregation takes. Your oil life does not care how many hours, how many starts...It is based on revolutions and provides a penalty factor for revs during warm-up time (cold to equilibrium) and temperature above equilibrium (during heavy load, high outside temp, and / or hot running engine due to coolant issues etc. Finally, there is an upper limit in miles established as to trigger C-O-S light and it is generally around 15K..I doubt you'd ever see it go 30K.... I run my Tahoe on freeway speeds 65-70 for 40 miles each way to work, and mixed with about 10% city traffic and mine tripped at 8500 miles.
 

toyo

Thread starter
Messages
133
Location
Gainesville, Georgia
When I changed my oil last time I did not reset the light on purpose. I wanted to see how far it would go before it came on. Mine does not show %, just a light. The olm system doesnt care how much oil you have in sump pump. You could have a 20 qt system and its not going to change the parameters. The new Mercedes system, called ASSYST, calculates oil change intervalsbased on driver-specific dats, and supplements that information with a sensor that continuosly moniters oil level, oil temp and dielectric number of the engine oil. In a nut shell there is a sensor in the oil pan that reads the metals, water, coolant, each of which have a different dielectric reading. So yes there is a system that reads what is actually in the oil.
 
Messages
1,904
Location
Bay Area, CA
quote:
In a nut shell there is a sensor in the oil pan that reads the metals, water, coolant, each of which have a different dielectric reading.
The dielectric value of the oil cannot tell you all those things you listed. It is a single value. BR5 gave the definitive link on the GM OLM. OTOH, I bet ********* would tell you that GM V6 engines are not prone to leaks.
 
Messages
7,409
Location
Austin, TX
quote:
The olm system doesnt care how much oil you have in sump pump. You could have a 20 qt system and its not going to change the parameters.
Are you sure? My understanding is that it's calibrated for the particular engine and it's configuration.
 
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