Oil life question

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Fless

Staff member
Super Moderator
Joined
Apr 2, 2017
Posts
12,155
Reaction score
24,781
Location
Elev 5,280
Short trips and lack of full warmups will contribute to decreased oil life. I'm not sure what the oil life monitor uses to calculate the percentage, but I would think it would take some of that into consideration. Otherwise it's useless.
 

wjburken

Supporting Member
Joined
Dec 26, 2017
Posts
10,051
Reaction score
28,032
Location
Eastern Iowa
Do you have remote start? If so, how much are you using it? You're not putting miles on it, but the motor is still running.
 

Geotrash

Dave
Supporting Member
Joined
Feb 16, 2018
Posts
6,511
Reaction score
16,204
Location
Richmond, VA
Short trips and lack of full warmups will contribute to decreased oil life. I'm not sure what the oil life monitor uses to calculate the percentage, but I would think it would take some of that into consideration. Otherwise it's useless.
Curiosity got the better of me and I found this on another forum:

The GM OLM calculates an OCI based on idle time, engine revolutions, oil temp, coolant temp, ambient temp, oil pressure, and some other things. If it overheats, the OLM immediately goes to zero, upon reaching 260F.

Since the 2010s, GM also started including hard limits into the OLM: most GM cars from the past 10 years or so will have a max OCI of 7500 miles or one year, except the Volt, which has a max OCI of 2 years and no mileage limit. The hard limits probably started when GM introduced dexos oils, after they had some problems with the HFV6 timing chains from long OCI suggestions.

Older pre-dexos GM cars with the OLM didn't have any hard limits programmed into the computer, but suggested not to exceed a year or 12k.

More reading here:
 

j91z28d1

Full Access Member
Joined
Feb 28, 2022
Posts
3,223
Reaction score
4,005
Curiosity got the better of me and I found this on another forum:

The GM OLM calculates an OCI based on idle time, engine revolutions, oil temp, coolant temp, ambient temp, oil pressure, and some other things. If it overheats, the OLM immediately goes to zero, upon reaching 260F.

Since the 2010s, GM also started including hard limits into the OLM: most GM cars from the past 10 years or so will have a max OCI of 7500 miles or one year, except the Volt, which has a max OCI of 2 years and no mileage limit. The hard limits probably started when GM introduced dexos oils, after they had some problems with the HFV6 timing chains from long OCI suggestions.

Older pre-dexos GM cars with the OLM didn't have any hard limits programmed into the computer, but suggested not to exceed a year or 12k.

More reading here:


volt limits are wild.. I'm surprised it says 2 years. I sware I've gone longer than that. one of my changes was at 26k the next at 65k and 84k

Gen 1's are a tank. sadly Gen 2's are like a ls after they added afm lol.
 

Marky Dissod

Full Access Member
Joined
Mar 3, 2023
Posts
2,022
Reaction score
2,813
Location
(718)-
The GM OLM calculates an OCI based on idle time, engine revolutions, oil temp, coolant temp, ambient temp, oil pressure, and ...
... some other things ...
Like WHAT? Damnt! Thanks, GM.
If it overheats, the OLM immediately goes to zero, upon reaching 260F.
Cheezits Greisd. Overheating is 239F! Damnt again! Thanks again, GM.
And what's in Marvel Mystery Oil?!?!?!
ANYWAY ...

"Change the oil every 3000 miles" can only mean the exact same thing to the two vehicles sharing the exact same drive cycle.
Miles are so easy to count. Everything ELSE the Oil Life Monitor is counting is nearly impossible for normal drivers to count ...
... but ...
3000 city miles stuck in Manhattan or Los Angeles stop'n'go with several cold engine restarts a day simply HAS to be far worse for the engine than 4500 highway miles where the only reason to stop the vehicle / engine is to refuel and every restart is warm because the tank just got refueled.

I very much like the IDEA of basing the oil (and filter changes) on more factors than just miles ... in principle.
Then again, if GM says overheating is 127C - 260F? REALLY?! - the OLM's other calculation ceilings / margins are also likely too high / long / otherwise generous.

I say overheating is 239F, damnt; 9% less than GM says. Imagine if there were 9% less warped heads ...

... to be continued ...
 

Marky Dissod

Full Access Member
Joined
Mar 3, 2023
Posts
2,022
Reaction score
2,813
Location
(718)-
Most NYC cabdrivers / livery drivers / chauffeurs apply the following 'skew' to the Oil Life Monitor:
If mileage is mostly all highway miles (NOT NYC), they'll change oil when the oil life monitor hits 17%, but NEVER over 5000 miles.
If mileage is more highway than local, they'll change oil when oil life hits 20%, but NEVER over 4000 miles.
If mileage is more local than highway, they'll change oil when oil life hits 25%, but NEVER over 3500 miles.
If mileage is mostly all local miles (NYC, 5 boros, stop'n'go, LOTS of idling, but also lots of restarts), they'll change oil when oil life hits 33%.
If they intend to keep that car after the lease is up, they may change the oil as often as every 2500 miles.

In all the years I've ever driven for a living, I NEVER met another driver for hire who would let the Oil Life Monitor hit 15%.
In all the years I've ever driven for a living, I NEVER met another driver for hire who would change the oil and filter AFTER 5000 miles.

In a previous post I mis-stated that "Monthly oil changes are normal for them."
What I meant to write was
An oil and filter change every five to six weeks is normal for NYC cabdrivers / livery drivers / chauffeurs.
 

Foggy

Full Access Member
Joined
Jul 25, 2019
Posts
1,106
Reaction score
1,425
Location
KS
I did reset the oil life gauge bc it was at 40% when I changed it last in August and there’s no way it used only 3% in 5-6 months.



Yes to answer your question I do do a lot of short trips and idling and it is really cold here about 20° on average and been dipping below freezing lately. But my oil doesn’t look like 37% oil life?
Been almost 5 months.... IMO, doesn't matter what the oil life monitor says...
Change That Oil !!!
 
OP
OP
iboughtatahoe23

iboughtatahoe23

Full Access Member
Joined
Feb 17, 2023
Posts
815
Reaction score
437
Been almost 5 months.... IMO, doesn't matter what the oil life monitor says...
Change That Oil !!!
The oil looks fine though. I’m confused guys. Less than 2k miles on the oil and yall say change it? Only thing I can think of is half idling and other half is due to restarts. I try not to let it idle. It is very cold where I am from in northeastern South Dakota
 
OP
OP
iboughtatahoe23

iboughtatahoe23

Full Access Member
Joined
Feb 17, 2023
Posts
815
Reaction score
437
I want to say run it because my job uses all third Gen Tahoes and suburbans for our shop trucks because we travel around the state and we sample grain from grain elevators and we’re partnered with BNSF railway and agtegra locations

Anyway, these are invincible you know we run the oil up to 10 K miles some times. Highway miles tho. And they’ll take the beating no issues and if anything happens, we just slap a new engine in it and go.


I want to say I’m good and it’s just due to the cold weather and idling and a lot of stop and go traffic because I do not travel outside of town at all guys.

The 2008 Burban is pushing over 300k at my job lol
 

Forum statistics

Threads
132,730
Posts
1,873,292
Members
97,559
Latest member
blanchard7684

Latest posts

Top