Yet how does one know if a change "is needed" at that time if the OLM does not say to change it? I can see GM relying on that 7,500 mi "check" to put it back on the owner if something came up pertaining to warranty coverage. Just the way GM has operated over the years. Like I mentioned in a previous post my 2011 manual has no mention of recommended mileage at all, just follow the OLM or 1 year.

Maybe someone that has put at least 7500 miles on the car in less than 12 months can comment about any remaining percentage left on the OLM. I was never able to put 7500 on my C7 in a year or so far on the C8. We just don't have that long a toy car driving season up here for me to get those kind of miles on mine.

Yes that statement alone does not define "if needed". But there is this "When the remaining oil life is low, the CHANGE ENGINE OIL SOON message will appear on the display. The oil should be changed as soon as possible." and this "When the system has calculated that oil life has been diminished, it indicates that an oil change is necessary. A CHANGE ENGINE OIL SOON message comes on. Change the oil as soon as possible within the next 1 000 km (600 mi)." In other words, its needed when the message appears. I agree its really unnecessary to check it at any specific mileage - but it is necessary to pay attention to the message when it appears, regardless of mileage.

I don't think anyone has ever reported getting to 7.500 miles from the last change and not seeing a change oil soon message. My guess is it will always go to 0 at or before 7,500 miles. If you don't drive so much, its going to be dominated by the 1 year requirement. If you drive a lot (more than 7,500 miles in a year), it will be dominated by a combination of miles, revs, temperature the items stated in the manual ("This is based on a combination of factors which include engine revolutions, engine temperature, and miles driven").

As Andy noted there is NOT mileage number. The OLM will display on the right side of the dash when there is ~10% oil life left. Have to press OK to cancel. It will do that every time you start the car decreases the %. You can always check the dash display for % Life Lift.

It's ONLY the OLM which is much more sophisticated and complex than simple mileage. Miles have never been a good indicator but all we had. :Let's see where those good highway miles with few stats and stops and only ~75 hp propelling the car at a steady 70 mph? Or were they poor stop and go City miles with many starts and stops. Nope mileage is not a great indicator. For example:

• The OLM monitors the oil temp after a cold start
• If the car frequently is used for short trips and the oil does not get hot enough long enough to evaporate much of the water of combustion
• It shortens the 12 month minimum time to change.

It also used total revolutions and other variables in addition to miles.
My 1993 Vette before there was an OLM stated this in another way in the Owner's Manual (See Below)

• If most drives are less than 4 miles
• When most trips are in stop and go traffic
• When it remains below freezing and most trips are less than 10 miles

CHANGE OIL EVERY 3000 MILES OR 3 MONTHS WHICHEVER OCCURS 1ST!
So Garage Queens that are only driven a few miles to go to the store need to change more often. The OLM will say change sooner than 12 months. Fellow who worked with the GM engineers who developed the OLM said there are a number of things it monitors that can decrease time to change BUT NON that increase!

FROM THE 1993 VETTE OWNER'S MANUAL
https://cimg7.ibsrv.net/gimg/www.cor...08087f9e05.jpg

The C7 service manual indicated that the maximum TIME before the OLM would count to zero was 12 months, and the maximum MILEAGE before hitting zero was 7500 miles. I haven't looked in the C8 manual, but suspect the same is true.

It says this "If driven under the best conditions, the engine oil life system may not indicate the need for vehicle service for up to a year,", and it says this "Under severe conditions the indicator may come on before 12 000 km (7,500 mi)." As far as I can tell that latter statement only appears in the 2024 Owner's Manual. It is the closest statement I have found to saying, or suggesting that the maximum is 7,500 miles. I'm pretty sure the max is 7,500 - its just not stated explicitly.

Every 6 months regardless of miles for me.