I’m new to the site. I’m guessing this has already been discussed many times.
I have a 2022 C8. Purchased 10/8/2021.
I have 2800 miles on it.
Manual says oil change should be done at 7,500 miles or at least once a year.
GM has extended their free first service to 24 months.
I have not checked the oil life % yet (didn’t know there was one until a few minutes ago), but I do get the “change oil soon” display. I’m guessing that is based on time and not actual oil life.
So, my question: do I adhere to the “at least once a year” requirement or do I check the oil life % and go with that?
Thx
JUST CHECKED OIL LIFE %. It is down to 6%.
Why so low with just 2,800 miles?

 

If it is like mine, they will be coincident - with low miles, and benign driving habits, the oil life indicator will decrement based on time and get to zero at one year. But - if that did not happen, hypothetically, I would go with whichever happened first. The manual is clear about the 'at least once a year", and also clear about whenever the oil life indicator says so.

By the way, they did not "extend the first service", they extended the expiration time for the first free service. The maintenance requirements were not changed. People debate what to do, but I opted for the full free service (engine oil and filter, transmission fluid external canister filter change which should include a hydraulic system flush procedure) at 1 year and 2500 miles, I will change the transmission fluid external canister filter again at 7500 miles which will be about three years, at which time the transmission fluid will be changed as well due to the three year requirement.

 

Adding to post 2, the 2022 manual never says change the engine oil at 7500 miles. It says at 7500 miles to check the oil life indicator and change "as needed". So, that, in combination with the 1 year requirement, simplifies to once per year, or whenever the oil life monitor tells you to change it.

 

I did 500 miles free , and 3500 miles @ 135.00 and will do it again at 6500 .. And the trans oil and filter at 7500 ..

 

Go by the OLM % indicator for the oil/filter change. The DCT canister filer change is at around 7,500 miles. For those that will be storing their car during the winter months, an oil/filter change is usually recommended as well. The first "Free" oil, filter, and DCT filter change offer has been extended up to 24 months or 7,500 miles after the initial in-service date of your C8. Ideally, get the "Free" service offer scheduled and done no later than 6,500 to 7,000 miles due to the current parts shortages.

 

There is a requirement to change the transmission fluid external canister filter at 7500 miles. If you have a 2023 model, there is a transmission fluid filter life monitor that should also tell you that. But regardless, its 7500 mile for the first filter change. There is NO stated requirement for changing the transmission fluid at 7500 miles. For transmission fluid, all models have a transmission fluid life monitor - that should tell you when to change it. There is a stated requirement to change the fluid at three years, and whenever the transmission fluid filter life monitor says to change it. In the 2023 Manual there is also an explicit statement to change the transmission fluid at 45000 miles. No harm in changing it at 7500 miles if that is what you want to do, but no requirement either.

I reviewed all of the maintenance requirements related to engine oil and filter, and transmission fluid and transmission fluid external canister filter changes in the 2021 and 2023 manuals and summarized them in a table, with page numbers where the supporting statements can be found in the respective manual. I believe that the 2020, 2021, and 2022 manuals have the same statements, but on different pages. But, the 2023 manual has changed the wording - it deleted the maintenance chart with specific odometer readings, added a transmission fluid filter life monitor, and some slightly different wording in some cases. I have posted it before, but here it is again. I'm not suggesting you follow what I put in the table - rather - I am offering this table as a guide for finding the maintenance requirements in your manual - they are all over in the manual - and this summarizes them. If you see something in the table that does not seem quite right, you can go to the page number in the manual and read the supporting statement for yourself.

 

I did my first at 2500 miles when I put on aftermarket exhaust and it was very dirty. Glad I did it. Once a year or every 5k from now on.

 

Just posted the following on another similar thread!

Fact is the C8 engine oil/filter change has little to do with mileage! IMO GM screwed up by putting engine oil/filter change in with the 7500 miles! BUT that is NOT the only issue with what has many errors!

It makes some folks think about the "Old Days" when the only indicator we had was the Odometer Reading and Time! Fact is the OLM uses many other things than miles. Like cumulative engine revolutions that are a far better indicator than miles. Also Gee, were those "good highway, few stops miles" or much worse for engine and oil, city stop, go, idle miles etc!??

Yep, perhaps if you reach 7500 miles it will say change BUT for my C6 and two C7s miles were never mentioned, no confusion it was when the OLM said change. As with the C8 IF you read when the engine oil/filter are to be changed! THE OWNER'S MANUAL CLEARLY STATES WHEN THE OLM SAYS SO!

The 7500 miles is referring to the DCT filter change. That should have been stated in a separate section etc.

You're changing engine oil max 12 months NOT because the oil is worn out it's for additive depletion and contamination. Same for my 1st Vette a 1988 that used miles because that was all that was available BUT ADDED CHANGE OIL AFTER 12 MONTHS WHICHEVER OCCURED 1ST! Another thing the OLM does, it monitors oil temp after cold starts and IF it does not get hot enough long enough to evaporate much of the water of combustion that passes the cold pistons it MAY SHORTED THE 12 MONTHS. That water and rich fuel mix from a cold starts can combine with the sulfur in oil and gas to form corrosive sulfuric acid.

Perhaps what it said in my 1993 Vette Owner's Manual will put that in perspective. Without a very sophisticated OLM all they could say was IF most drives were less than 4 miles CHANGE OIL AT 3000 MILES OR 3 MONTHS WHICHEVER OCCURED 1ST! (SEE manual page below.)

From 1993 Owner's Manual before the OLM was used for Vettes. C8 OLM monitors oil temp after cold starts and IF it does not get hot enough long enough to evaporate much of the water, a major combustion product, it will shorten that 12 month change requirement.

 

Car delivered 10/29/21
First oil change 3/1/22 @ 2,514 miles - I used my rewards points to pay for it.
Current mileage is 4,000 as of (9/24/22); Oil life monitor shows 43%. Transmission fluid shows 88%.
Since I did my 1st oil change within the first year, my next change will be the free one, depending on mileage and oil life %.
I'll do the oil and transmission filter service (not fluid) before 3/1/23 as I'll be much closer to 7,500 miles by then. (Need to drive it more)
Make sense?

 

To simplify, get the free oil change and new transmission filter near to but before 7500 miles within the first two years. All other oil changes do them yourself or at your cost.

 

The Oil Life Monitor subtracts 8% per month, regardless of miles driven. So after one year, the OLM will always show 0% even if it’s not driven once within a 12 month period. Since you’ve owned your C8, the original oil has been in the vehicle one year. GM and Mobil 1 have concluded that your one-year old oil no longer meets the minimum lubrication requirements. Change that oil!

 

I'd love to see the lab work that "proves" the oil degrades in the engine enough to not be effective after 12 calendar months.

Wouldn't be surprised if much of the spent 12 mo old oil is sent to a filtering/processing company and resold as an off-brand as new.

 

^^^
Hmm, you are NOT changing oil because it's warn out at 12 months if you put on say 3000 miles. BUT before the OLM my 1993 Vette said IF most drives are less than 4 miles change oil ever 3 months! How does that hit you!

You are changing min 12 months due to:

1. Contamination
2. Depletion of additives

My 1988 and 1993 Vette said change at xxxx miles or 12 months whichever occurs 1st! Miles are actually a silly indicator, are those good highway miles of bad city miles with lots of starts stops etc?? But it and time is what we had.

My 1993 tried to deal with the worse contamination, cold starts and NOT allowing the engine oil to get hot enough long enough to evaporate much of the key product of combustion the passes the cold pistons WATER. In addition the fuel/air mixture is rich to keep combustion going until the ~2500F combustion temps heat and expand the pistons and allow a leaner mixture. One key product that forms is sulfuric acid as water combines with sulfur in oil and fuel! Stuff is corrosive when car is just sitting!

The OLM actually measures the oil temp after a cold start and IF IT DOES NOT GET HOT ENOUGH LONG ENOUGH will lower that 12 months! BTW, the OLM although miles may be an indicator is also using total revolutions a much better indicator. In fact if you look you can actually see the total revolutions number!

Yep worse thing for a "garage queen" is starting the car pulling it out of the garage to get something and pulling it right back. Or driving two miles to a store and think I'm being good to the engine and oil. NOPE!

 

Of course! And we would certainly want to be changing the oil well before "" the oil degrades in the engine enough to not be effective after 12 calendar months." Hopefully the lab work that was used to establish the 1 year interval showed only a small percent degradation in the capability of the oil to meets its specifications.