So I have an 02, and for my vehicle the OLM is based off only two things: Oil temp and RPMs. Whether or not your newer model includes all that extra, I don't know. (We didn't even get all of that before 03).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:
GM's Oil-Life System Improves Timing of Oil Change
This past November General Motors announced the expanded inclusion of its oil change indicator on 90% of their production over the coming five years. The Oil-Life System is currently in use on some...www.machinerylubrication.com
It's winter time, so I would expect that Oil life to be reduced.
IMO, that OLM is not for "us". It's not for car guys/gals. It's not for people who care enough about your vehicle to come on to a website and learn about their vehicle. It's a dummy light for people who need to be told when to take their vehicle into the dealership. It's not for people who change their own oil; if you do, keep your own records.
Personally, I can tell when it's time, and if you want to learn, you can check the dipstick to keep an eye on the color, or even better a catch can with a quick window.
Last, also know that the OLM has NO CLUE what kind of oil you put in there. If you put in dollar store brand conventional, or you put in Amsoil synthetic, you're going to get the exact same timer with the exact same oil life according to that countdown. Keep your own records, here's what I just keep a notepad file for:
268,869 THROTTLE BODY CLEANED (22May2023)
268,869 MAF CLEANED (22May2023)
268,869 AIR FILTER CLEANED (22May2023)
269,383 BRAKE LINE REPLACED -USED/PULLED ACROSS REAR AXLE. (06Jun2023)
269,383 CLUTCH BLEED LINE REPLACED - TICK PERFORMANCE LS1 KIT (06Jun2023)
269,383 BRAKE FLUID FLUSHED - DOT 4 LIQUID MOLY #22078 (FOR FUTURE - 2 QTS > BRAKES AND CLUTCH LINE) (06Jun2023)
269,383 OIL CHANGED PENNZOIL PLAT FULL SYNTHETIC 5W30 6QTS WITH FRAM EXTRAGUARD FILTER (06Jun2023)
269,383 TIRES ROTATED - BACK TO FRONT, FRONT CROSSED TO REAR. 45 DSF, 44 PSF, 40 REAR (06Jun2023)
269,383 SHOCKS ADJUSTED FRONT QA1 - -1 COMPRESSION, +1 REBOUND (06Jun2023)
