Oil Life Monitor - Strange!
 

I took delivery of a brand new 2019 Z06 on April 10th (it had been built on March 21st). The oil was changed in May at 500 miles and the monitor was reset to 100% at that time. By August 23rd I had a whopping 835 miles on the odometer (there are two other Corvettes in my garage). I left for Carlisle that night and noticed that the oil life monitor was at 75%.

Got back from Carlisle on August 25th, The odometer read 1,810 miles...however the oil life monitor was now at 74%.

I find it strange that after driving almost 1,000 miles the remaining oil life fell only from 75% to 74%. Could it be that it was playing "catch up" due to the loss of 25% based upon time form May to August when the car had barely been driven??

You are exactly correct. It takes a lot of factors, variables, and conditions, including time, into account.

There's nothing strange about it at all. It's time, type of use, and mileage-based. If you change the oil and park it for a year, it will be at approximately 0% with no miles between changes. The way you drive also affects it. If you drive very aggressively at high rpms, it will need to be changed at less mileage than if you drive conservatively.

Most of the approximately 1K miles you put on it in a few days, were low rpm highway miles, no doubt. You may be able to go 12K miles or more within a 1 year period between changes if it's all highway miles, and only 5K if all your miles are stop-and-go 1/4 mile "street racing."

Just posted this on anothr thread re C7 keeping track of time. Actually my 1988, 1993, 2008, 2007 and current 2017 Vette all said in the Owner's Manual, change oil in max one year. The C7 is just the first to keep track of time for you!

An old post by "Bob the Oil Guy" who worked with the PhD from GM who developed the OLM system said they used a number of measurements and engine use parameters to define things like how the ZDP (an anti-wear zinc/phosphorous compound added to oil) is depleted with use. He did say they use rpm and an other important variables to define when the oil should be changed. A key one defines why oil should be changed in a maximum of one year (or sooner as defined if all drives were less than 4 miles trips in my '93 Owner's Manual that said change every 3 months maximum!)

In that case, it's not the oil or it's additives wearing out or depleating it's the acids etc formed at every start that cause engine metals to corrode! I'll provide a detailed explanation for those interested below:

DETAILS:
I know some will roll their eyes :crazy: over this technical explanation and skip but for those that want to know, this is what happens in the engine at a start:

The aluminum pistons and engine block are cold when started. Since the pistons will soon be exposed to ~2500 F combustion gases they will get hot and expand quite a bit. The gap between the pistons and steel cylinder liners when both are cold is purposely large as the pistons will expand and reduce clearances a short time after starting.

The combustion products like CO, CO2 and the water that forms between hydrogen in the fuel and oxygen in air blow past the pistons and rings -much more when cold. For every gallon of gas a bit over a gallon of water forms (those 2 Oxygen atoms for every Hydrogen atom in the fuel are very heavy!) That water will combine with the sulfur in the gasoline and oil (yep same sulfur that can coat the fuel sender.) That forms corrosive sulfuric acid. If the engine oil gets hot enough, long enough much of that water evaporates. However if the Vette is mostly driven on short trips that does not give it a chance to happen. So instead of the "guess" in the '93 Vette Owner's Manual of :change oil every 3 months," the OLM keeps track of starts and the oil temp reached after a start. If it does not get hot enough, long enough it will shorten the mandatory max one year time.

There are no doubt other measurement factors used as well but regardless of miles driven the OLM will say chage oil 1 year (or sooner) from the last change.

That's false information you've posted, along with JerryU.

My new C7's factory oil fill is now 25 months old. The OLM reads close to 50%.

Neither of our C7's situations is explained away by the "stock answer" posters above. Yours (OLM) is certainly as odd as mine. I don't have the answers, but I'm certain they don't either.

As usual, you are the one posting false information Joe. You haven't even owned your car for all of those 25 months, you have had it less than a year. Your dealer reset your OLM to 100% when he sold it to you, I guarantee that's the case. There are literally thousands of C7s owners on this forum that can confirm that the OLM counts down to zero by the one year mark (at the latest, if the mileage doesn't take them there first)

How many times have you reset the OLM Joe?

You're the one who keeps giving false info, and outright lies, in every oil life monitor thread here.

I find this funny because I change the oil in my lawn mower more than Joe does in his Vette... Anyone who wants to truly care for their Vette, please do exactly the opposite of what this member posts..:pistols:

I find it funny that you seem to think you know when others change their oil. :rofl:

Well then Steve R., maybe you should prove the OLM claims false then? Facts are what they are.

Prove what, exactly? Fact: The OLM will go from 100% to 0% in a year whether you drive it or not. Fact: GM recommends changing the oil at least once/year no matter what. Fact: GM can deny engine warranty claims if you don't do the maintenance at least as often as they specify.

What other facts need to be explained or proven Joe?

:lolg:

Ummm...YOU said you haven't changed your oil in two years...here and in other posts...so Im hearing it from the "horses mouth"... As for others...No one, and I mean NO ONE has posted they leave their oil in their Vette for two years or agree with you in any capacity...so sorry, you're all by yourself on that train...:trainwreck:

The car's computer uses a complex algorithm that I've never seen fully explained. But, that aside, I give up, why not just follow the car's (GM's) recommendations: hardly that big a deal. It won't get you into any trouble doing so. :thumbs:

Today - 3000 Miles - 65%

Changed oil and filter - Reset Oil back to 100%

I will redo next month.

Mobil 1 5W-30 - PF64 filter.

Ok - Now bash me for changing my oil every 3K miles...
I don't care. It is my car and I will service it every month at 3K miles whether you like it or not.

The next owner will appreciate it when I sell my high mileage corvette very cheap with a sh1t-ton of records.

It is not false info. The OLM is designed to get to zero even if not driven at the end of a year.

As many of us posted, your car is either malfunctioning or the OLM has been reset.

When you have all the tools and the oil and filter are less than $50 at Walmart why not? Takes very little time.

PS: Mine is 75% at 2000 miles.
.

^^^

Not bashing, your car, your choice BUT if you use the Mobil rebate of $12/5 quart jug (2 allowed), oil is <$2.50/quart so most for 10 quarts = $25 and ~$5 for the PF64!

In my case a DIY is much quicker than going to the dealer and also risking 1) cracked rocker panels, 2) using the non Mobil 1 oil pumped from 55 gallon jugs of some brand dexos certified oil blend, and 3) possibly overfilling.

Also, since if filled at the rate as works for a wet sump, it's too fast for a dry sump (99.5% of what that newbie tech who works the oil change bay does) and oil spills over the dry sump tank! Very hard to clean in the small space between the tank and the firewall. That leaves oil close to the flimsy plastic cover for the cabin air filter. When the tank oil gets hot it heats the outside spilled oil and many complain about smelling oil for weeks after a fill until all that oil goes away! :lol:

You have to be one of the top 10 clueless individuals participating in this forum.