Walt White Coupe

When I get mine inspected yearly, I have my independent shop change the oil & filter that I provide. They charge me $15 for the service. I get the oil when Mobil 1 has their discounted price specials. That and a filter is around $30 for the base model.

Gearhead Jim

It's an interesting world.
My work life was in airlines and law enforcement. For both of them the mantra is "If it's not documented, it didn't happen."

kitesurfer

I just did that yesterday with my van. I've got one m ore free oil change from chevy and then off to the bad side of town

Eff A Ford

Dealer called me at 18% to schedule an oil change.

TEXHAWK0

I usually let mine go to st least 4000 miles, even if OLM is at 0% if not over a year since last change.

LDB

I’m a latecomer to this thread. I glanced at it early, and it seemed to be the usual interval silliness, so I haven’t looked again until today. My experience at one of the big oil companies is that the few, really senior technical types keep their eyes on things. They let a lot of minor details go by, because as many have said in various ways in this thread, you don’t have time for everything. On the other hand, they don’t let fundamental and/or serious errors go by. So if I apply that thinking to this thread, can I imagine that there are debates down among the weeds about exactly what functionality the OLM should have? Sure. But can I imagine that it’s seriously wrong? Nope. And I say that from two standpoints. First, the analogy that I wouldn’t have let a serious error go by in such an important function. Second, the fact that I know from my own oil company’s testing that 25 spread full synthetics (such as 5W30) are perfectly ok for intervals even longer than come out of the OLM’s. I might start getting sweaty palms with dino oil or ultra wide spread oils like 0W40, but that’s a different issue. And the issue of time interval for very low mileage cars is a toughie. It really boils down to how those low miles are driven. If it’s a super-short daily commute to an office 3 miles from your house, you are probably at high risk. But if it’s just rare use, but when it’s used, you get the oil thoroughly hot (>170F on oil, the coolant temp is totally irrelevant), then you are probably ok for well over a year.

Vetteman Jack

No harm in waiting until it says 0% oil life remaining, but change it now if you feel like it. Either way, your car will be fine.

Foosh

Great post, and I fully agree. The only other thing I'd add is that it's very smart to follow the manufacturer's guidance for your own protection.

rrsperry

Why do people say that? The people that wrote the manual are accountants, marketers, and lawyers, run past a technical writer. With a little input from an actual engineer.

They write the manuals so that they can get the cars out of the warranty period with as few claims as possible. They DO NOT CARE about ensuring best performance, longevity, or service life. In fact, I believe they would be perfectly fine with having the car be ready to be replaced after warranty so they could sell you a new one. (but that would look shady...)

MikeyTX

Don't drive it in Houston. You could end up with a worse issue ..........

Walt White Coupe

Quote:

Originally Posted by rrsperry

Why do people say that? The people that wrote the manual are accountants, marketers, and lawyers, run past a technical writer. With a little input from an actual engineer.

They write the manuals so that they can get the cars out of the warranty period with as few claims as possible. They DO NOT CARE about ensuring best performance, longevity, or service life. In fact, I believe they would be perfectly fine with having the car be ready to be replaced after warranty so they could sell you a new one. (but that would look shady...)

This is what anti-intellectualism looks like.

LDB

You are correct in saying that engineers don’t write the manuals, but you are incorrect in concluding that means the manuals are unreliable. Sure, the engineers chuckle and look down their noses at all the lawsuit and marketing related silliness that often stoops to things pretty close to saying don’t step on the accelerator if there’s a small child standing in front of the car. And also sure, the engineers aren’t going to care much about how a manual writer describes functionality of the interior lights and switches. But if you’re talking about a significant technical issue like oil viscosity, change interval, or the like, of course they care, and of course they make sure the manuals are correct on the fundamentals. If you think they don’t, you have just called the engineers who designed your car some combination of uncaring, ineffective, and incompetent. That in turn would make me ask why you bought the car in the first place.

LT1 Z51

And this is why I don't support the current time component, as I fall into the latter category (when my miles are low).

2 years to me, seems a happy medium unless the former is so toxic that it has to weigh down the time component like a boat anchor. I don't think it should, or at the very least, I should be given a choice.

The beauty of the old OLM was that you the user could make a decision on time, and the car would make an educated guess on the other factors (I disagree that OLM's are perfect, good, yes, but perfect no).

Patman

History has proven that the OLM is set up correctly in the Corvettes. Go into the C5 and C6 section and ask how many people have followed the OLM and have a ton of miles on their cars with no issues. GM does not want your engine to die as soon as you come out of warranty, they want you to be a customer for life, so having it die is not in their best interest whatsoever. So they most definitely do care about longevity, do you really think someone is going to buy a new car from the same manufacturer if their previous car's engine dies right after the warranty is up?

LT1 Z51

What an engineer categorizes as fundamental and what a user categorizes as fundamental are not the same thing.

In terms of the owners manual, what you can always count on being correct is the capacities and the specifications for the fluids which should be in it.

The maintenance intervals are copies and the same in nearly all manuals (Corvette has a modification now for the 500 mile oil change, but otherwise that page is the same old same old).

And I've met plenty of engineers (specifically AT GM) who are uncaring, ineffective, and incompetent. So you'd be right about that.

Patman

As I have mentioned here on the forum a number of times, since my C6 is out of warranty and since I'm a bit of an "oil analysis nut", I have been doing 2 year oil changes with this car. On my most recent oil change I went 2 years and 10,000 miles, and the oil analysis results proved it was safe. I'm not recommending anyone on here do this while under warranty, but once you're out of warranty if you're always taking the car on longer trips whenever you do drive it, but you're only putting a couple of thousand miles a year, I think you're perfectly safe to go 2 years if you wanted. I'm pretty sure very few people here will ever do that.

PetroniDE

With all my cars, usually near 25% at the 5000 mile mark.
I change mine every 5000 miles or when it gets to 25% (especially if I have trip with significant mileage planned).

Extra dollars spent worth the piece of mind, IMHO.

LT1 Z51

I'm struggling not to laugh.

Automotive companies are in the business of making money. They want your existing product to work within your expectation of how it should work.

The original owner has different expectations than the second, third, and fourth owner. This is factored into how the car is designed.

Tests are done at an "accelerated" rate which means they have a 90-95% confidence interval versus real life, but they aren't perfect. Nor are they designed to be.

The 80-20 rule is a real thing (you can get 80% of the functionality and quality for only 20% of the total cost). Every percentage increase over 80% is significantly more money. There is a point at which it becomes impossible (financially) to make things better.

C6_Racer_X

Interesting discussion here.

One thing that can sometimes be overlooked in the OLMS usage is the oil itself. The OLMS has a specification for the oil, and you must use oil that meets or exceeds the specification for the OLMS to deliver safe and accurate recommendations.

The C7's all use the later OLMS, which is specifically tailored to "Dexos-1" spec oil. You can use any Dexos-1 spec oil in the engine and the OLMS will tell you to change it before the oil has degraded to the point where it's insufficient for the engine. One reason the OLMS on the C7 seems to recommend oil changes earlier/more frequently than the earlier OLMS on the early C6 years is because the Dexos-1 spec is not as stringent as the earlier GM4718M standard.

The early C6 years used a different OLMS, with different assumptions about oil usage and a requirement for "GM4718M" oil (often called the GM "High Performance" oil spec). That earlier spec required full synthetic base oil plus a certain additive package. You need an oil that "meets or exceeds GM Standard GM4718M" for that earlier generation of OLMS (or did they call it EOLS back then). Beware synthetic blends or conventional oils that mention the GM4718M spec without the words "meet" or "exceeds." You'll see "blended to GM4718M specs" or "formulated to GM4718M specs," but the word "meet" will be conspicuously absent. Those oils may have the correct additive package in a conventional base oil package or a synthetic/conventional blend. They specifically do not "meet" the GM4718M spec, even though they have the specified additives, and if you use those oils and go all the way to "0% oil life remaining", you'll have the potential for oil related engine problems, including excessive wear and bearing failures.

That said, I really wish GM had given Corvette owners and other vehicle owners who choose to use synthetic oils a choice in configuration of the OLMS on the newer ones. If you actually use a better oil, you won't get the full benefit of the long life of the oil if you follow the OLMS.

I understand the switch. I was in the industry back in the late 2000's when the first generation of the engine oil life system came out. Many owners of more basic Chevy trucks and cars were highly annoyed that their vehicles required expensive synthetic oil.

LT1 Z51

My C6 required Dexos.

The change was done in 2008 with the LS3.

To be clear as well, Dexos is just the "next generation" of the GM4718M spec.