boss2k

Ok. I am of the firm believer that engine oil should be changed every 6 -8 months or 4-5k miles

owc6

Ok, gotcha.

If you drive it a hundred miles, it will tell you to change it at a year, if you drive it 3000 miles, it will tell you to change it at a year. If you drive it 5000 miles, it will tell you to change it at a year.
If you drive less than 8,000 miles a year, it will tell you to change it at the year mark. I think 7000-8000 miles (dry sump) is the tipping point. If you drive it more, then you will still probably get about 7,500 miles out of the oil before the OLM zeros out. For some of us, that is more than once a year. Track use not included in my observation.

Changing oil prematurely won't hurt, but may be a waste of your time and money. This OLM is pretty smart, so there is no reason not to follow it, IMO.

Carvin

I had a thread about OLM last week. I was surprised to see mine read 13% when I pulled it out of storage since my last oil change was in Feb 2018.
(I put it in storage in January and I think it had 20% or so showing)
One of the guys said the next time you drive it will go to zero and that is exactly what happened.
Sounds like a good one for those Vette trivia stickies.

orca1946

It drops that much in storage? WOW that's dumb!

JMII

There is a time component to the calculation.

I change it when it tells me to... around 4% remaining is when the warning popped up on the dash. Based on my current driving (daily driver plus a few track days) I should go about 7,500 miles between services.

Carvin

In my case it "zeroed it out". It goes to zero after a year regardless of what oil life remained when I put it away.

Frosty

If your car is under warranty and you have the on-star basic activated, does on-star send OLM data to GM so that it could be used aganist the owner in an engine failure warranty claim? Nor worried about it, just curious what is being sent.

Mad*Max

Based on what I have seen in my Cadillac ATS the OLM will take the worse of the two - time factor and oil "usage" - if the OLM has counted down from sitting around for a couple of months, driving it will not notch the OLM down until the usage factor catches up with the time factor.

In my C6 I had observed that 60 miles will bring down the OLM by 1% vs. 120 miles of strictly highway driving.

~Stingray

isn't synthetic supposed to last about 10k miles before changes. If I can go 5k miles on conventional, synthetic should be at least double that or at least once a year.

mschuyler

We have already established that the Oil Life Indicator has a time component that will zero it out after a year regardless of miles driven. That is not "dumb." It is working as designed to account for deterioration of oil after it is exposed to oxygen. The Corvette is spec'd out with synthetic oil. The factory fill is Mobil 1, and that is what you are expected to use. The Oil Life Indicator cannot magically tell whether or not you are using synthetic oil. Since it is set up assuming you will use synthetic oil, the idea of being "more lenient" is not a factor in the algorithm that calculates this. If anything, it ought to be LESS LENIENT if you use non-synthetic oil, but since it can't tell one way or another, it's a moot point. And No, OnStar will not tattle on you if you don't change your oil, but the car itself will. OnStar RECEIVES the information from the car, and this information is no doubt stored with the car.

The Oil Life Indicator is just a ticker, one of many. It does its voodoo calculations and tells you when it thinks you ought to change the oil. You can drive another thousand miles with it saying "0% left" and nothing will likely happen. If the engine breaks GM might not want to pay for it since you weren't paying attention, but still, you are in charge and you can do what you want. If your vast experience dictates that you ought to change your oil more or less often, you can do that. If you think the Indicator is "dumb" or otherwise don't like how it works, tough. That's not going to change how it works. You can lobby Tadge & Co. to change it if you want. IMO a prudent person who values a warranty would do what the Oil Life Indicator says just to maintain the warranty. But you don't have to do that, and if your warranty is expired GM is not going to fix it if it breaks anyway. But you can certainly be a rebel and defy that cursed Indicator and live free of such draconian requirements!

Or you can just change the damn oil!

Elk

Why is everything associated with oil so controversial?

Engines have had oil in them as long as they have been in existence. We all know the oil needs to be changed. Nothing new.

No one here appear to be more knowledgeable than Corvette's engineers when it comes to oil. So why the constant second guessing? Change the oil when the monitor tells you, using the specified oil.

This frees up your worrying energy for other critical issues, such as whether you want apple slices or Go-Gurt with your Happy Meal.

JMII

yep seems simple to me... I honestly don't get what all the noise is about

However with that said, I do understand those people who don't drive very often being upset that the oil gets "old" and has to be replaced despite the car sitting still. Tadge covered why here:

The simplest variable is the length of time the oil is in the engine. As you surmise in your question, this is an important variable. Oil ages sitting inside your engine differently than in a sealed container. It is exposed to more oxygen, humidity, various sealants and a variety of metals in your engine. Also, time causes things you might not expect to have an influence such as oxidation of your oil filter. To account for this variable there is an OLM clock that begins a year-long count down every time it is reset. So that is the best you can do…. Change your oil and filter once a year

ShadowGray19

Tadge quote here is excellent. Here is an Article from Amsoil that provides some more information on why time is an important factor for oil changes:

http://www.1st-in-synthetics.com/Tec...Not_In_Use.htm

JerryU

It’s not as much “hard driving” as short trips where the oil doesn’t get hot!

This whole, “why is my oil life changing?” Is best explained IMO by what it said in my ‘93 Vette Manual before the OLM:

Change oil at 7500 miles OR ONE YEAR, WHICHEVER OCCURS 1st.

If most drives are under 4 miles change oil at 3000 miles or 3 months, WHICHEVER OCCERS 1st

Your typically not changing oil because it’s Worn Out! It’s because every time you start a cold motor lots of combustion products from a rich fuel/air mixture get past those cold pistons, until they expand when they get hot. One product of combustion is water. Water mixes with sulfur (and other compounds) and forms sulfuric acid etc. If the oil gets hot enough, long enough after a cold start it evaporates much of that oil. The OLM takes that, engine revolutions and other factors into it’s algorithm. One of the worse things you can do is start the car to pull it out of the garage to get something and pull it right back in. My Street Rod mostly goes to Shows. I avoid doing that and will try to go for a ~20 mile ride if I need to move it out of the garage- and have fun.

The C7 was the 1st Vette to keep track of time (no doubt because many did not read, follow or understand the manual.). No big deal as in one year if you drive very few miles it will say change. Suggest those who don’t like seeing the reduction with time don’t look at it!! It’s doing nothing more than if you were to look at a calendar every day after you change oil !! Now if most drives are ~ 3 miles it will say change sooner. .

papillion

It's a guy deal. Obsessing over their car to the point of distraction. And the more arcane the discussion, the more worriers can be experts.

Walt White Coupe

I love my C7 but hate the oil life monitor system. Life is good. The C6 system was better. Probably the only thing that was better.