1bdvet

I change it once year, the DIC by then shows 49% and who ever has old on sale, or specials.

C6_Racer_X

It will have the "early C6" OLMS that I described. For that system to work properly, use full synthetic GM4718M rated oil (

I'm pretty sure that the whole 1 year expiration on the OLMS started with the 2011 model year. I know of a 2012 GS that definitely behaves like the C7's, burning through the oil life in a year, even when rarely driven. All C7's do that, but I pretty sure the late years of the C6's do it as well.
I would change it.

The issue for low mileage, older oil is pH. The "pH balancer" additives get used up as water from condensation accumulates in the oil and mixes with combustion by-products and impurities in the oil forming acids.

Getting things up to full operating temps (on a 10 to 20 mile or longer trip) will help evaporate the water, and minimize the formation of the acids. But the acids that have already formed will remain in the oil. There are "pH balancers" in the additives that will react with and neutralize the acids, but they are consumed (no longer present to continue neutralizing acid) when they react. The time component of the oil change interval is largely related to the consumption/loss of those pH balancers.

Bruze

The only way to tell which is "better" is under controlled laboratory conditions.

I bet if you used Mobil 1 you would have had "great results" too.

I bet if you used a name-brand dino juice you also would have had "great results."

I've had "great results" with all the oil I've ever used; meaning, I've never had any problems caused by oil, and that includes a lot of junkers that had unknown histories. My '61 Corvair leaked oil so bad that I used "remanufactured" oil to save money (I was 17). I did blow the tranny but that had nothing to do with the engine oil.

There is one exception, my '51 Fergie tractor. I bought it in '77 and in 2001, it got a sticky valve which ended up going through the piston. But it used non-detergent oil, which didn't help. Had I changed it more frequently, would it have helped? Maybe. But there is no hour meter on it so I had no idea how old the engine was. None of this is really relevant to modern cars using syn oil.

EVRose

Does "great results" mean the engine hasn't blown up? Using that scenario all oils produce great results since I don't think I've ever read on here a case where the engine was damaged due to a certain oil being used over another.

cb1980

I change the oil in my 07 every 5-6k miles, my 66 and 99 get changed at least once a year since they don't see that much mileage. I use mobil 1 oil and filter

windyC6

Yea....tell Judge Judy that all you have is a receipt that only proves that you bought the oil.....

windyC6

Even dino goes beyond the old myth of 3000 miles these days. Thats because the engines run so much cleaner.

LDB

This is sort of in quibbling range. The biggest single issue is indeed pH, and the pH stabilizers do counteract acid formation, but it’s only partially true that once formed, the acids hang around. We’re talking about various carboxylic acids, and most of them aren’t all that thermally stable. So getting the oil hot not only drives off the liquid water, thus preventing more from forming, it thermally destroys many of those that have already formed. But from a practical standpoint, our advice is the same. The more often you shut down your engine with oil temp below 160, the less willing you should be to push oil life limits, and the more you should consider using extended life oil for the extra pH stabilizers that go along with such oil. To be clear, you wouldn’t be using the extended life oil with the intent of going to high mileage between changes. You’d be using it because it has more pH stabilizers to give you more acid protection from frequent shutdowns at less than 160 oil temp. Note that there’s no advantage to that for most drivers since unless the pH stabilizers are depleted, you’re perfectly ok.

LDB

The biggest single factor in that is the advent of PCV. Not only does it give a huge pollution reduction, it makes the crankcase and oil environment much friendlier. Before PCV, the crankcase was essentially pure exhaust gas from piston blowby. Now the blowby is greatly diluted with the air sucked through by the PCV system.

Ramets

I mentioned Amsoil because of the results I've gotten. Not only did it quiet everything down, but in my Harleys they run cooler, and shift smoother. Even after 15,000 mi. the oil viscosity was near normal levels. I only went 15K once, and sent the oil off to Blackstone lab to be tested. In my C5 I sent a sample in at 8K and they said there was no reason to change the oil, although I did anyway.

mikeCsix

It's the water and condensation that can accumulate in oil when the car sits for long periods of time which requires the annual change.

HOXXOH

You are somewhat typical among Corvette owners, because you don't spend much time driving. When you do drive, the OLM doesn't consider miles or a calendar, but only what conditions the oil is being subjected to that affect it's ability to lubricate properly. Heavy loads and high RPM when the oil is hot will knock the oil life % down quickly. Multiple short trips with cold oil will do the same. The cold startup is the worst part of any trip, so short trips experience that more often.

As a DD, occasional drag racer, with fairly often road trips, I get about 120 miles per 1% of the OLM. More for lots of road trips and less for very few road trips.
With your 2200 miles and using up 30% of the oil life, you either take mostly short trips or the road racing track/drag strip you frequently visit is nearby. That works out to 73 miles per 1%. If it's those short trips, the bigger concern is letting the contamination stay in the engine for long periods and just adding to it on subsequent short trips.

windyC6

And how does that pesky water get into that engine ??......

Bruze

But what are you comparing Amsoil to? You need some "control" to compare against, and unless done under laboratory conditions even that wouldn't mean much.

"Quiet everything down." Quieted what? Compared to . . . ?

I started using synthetics in my '88 Softail in the late '90s, simply because they had been proven on the racetrack to be a better lubricant than dino oil.

Synthetic engine oil: no noticeable difference, nor did I expect any. The reason to use it was for less long-term wear.

Syn primary oil: No difference that I recall (no longer have the bike). I remember reading stories about it being too slippery and the clutch wouldn't work properly. But as usual, it was just another one of those urban myths because I didn't notice any difference.

Syn tranny oil: No noticeable difference. But again, I was using it for its better long-term wear properties.

However, FWIW: I have a 2-stroke jet boat; the RPM maxes out at 5100 RPM. I started using synthetic (don't remember the brand) in the fuel mix, and I gained another 100 RPM. So, no surprise, it *IS* a better lubricant.

I'm sure this would have been measurable in the Harley too, but they have no tach, and it was just a big heavy crusier. They're driven more like an old tractor than a race bike so none of that really matters, except that I got better wear resistance.

All examples are anecdotal (just like everyone else's) so take it FWIW.

windyC6

If memory serves, I believe the early syns had some issue that tended to help deteriorate gasket material, thus causing leaks in Hogs. And believe me, Harleys didn't need any help with leaks....LOL. Fact or fiction I don't know. But I do recall a few Harley buddies complaining about leaks after using it. But then again, how does one prove whats causing a Harley to leak ?.....

LDB

Piston blowby. See first paragraph of post #55. If I were going to be picky with mikeCsix, it would be that the problem isn’t the water per se, it’s the carboxylic acids that the presence of water enables. The water source is pretty obvious -- condensation while the engine is cold, of the roughly 25% water vapor that is in the piston blowby exhaust gas. All that water vapor in exhaust gas is why you see clouds of steam coming out of exhaust pipes in cold weather.

Lee Cromwell

I change mine because it makes me feel all warm and fuzzy when I get intimate with oil ! When it starts costing over $100 maybe I'll wait longer...but I doubt that too!

owc6

According to the 2013 OM, it does not zero out at a year (as it does on the C7s which uses calendar time as one factor), and still requires the owner to change the oil annually even if the OLM is not indicating a change is necessary.

P. 5-17
"It is possible that, if you are driving under the best conditions, the oil life system may not indicate that an oil change is necessary for over a year. However, your engine oil and filter must be changed at least once a year and at this time the system must be reset." bolding mine.

If you have something that indicates otherwise, please share.

Bruze

I recall hearing something like that too. Not sure if it had any truth to it and if it did, I don't know if they changed the oil additives or changed the gasket/seal material. Maybe LDB can shed some light on this.

As for Harleys leaking oil: Yes, an old tale, along with the British bikes. And I've seen plenty that did leak. But what I learned over the years:

- A lot of these old Harleys were decades old, with broken or non-existent speedometers so there was no way of knowing how many miles were on the engine.

- A lot of them were likely not maintained well, at least by some of their owners throughout their lifespan. My nephew bought a Shovelhead that was a total POS, all cobbled together, wires were just twisted together with electrical tape for "insulation," etc. I know a lot of the J A P guys would laugh at Harleys broken down on the side of the road, but there were reasons for it. They were, literally, POS, scabbed together for decades.

- A lot were "maintained" by guys who were hammer mechanics at best. That speaks for itself.

FWIW: I bought my '88 brand new. It was an Evolution engine, an improvement over the Shovels. It did not leak at all. I had it completely apart from one end to the other, mildly souping it (except for the bottom end, which is still virgin). I did have a slight leak from the rear valve cover, which was my fault and easily fixed, but the rest was fine.

I sold it in 2015 with around 57k miles on it to a guy I know. I just saw him a few weeks ago and he's lovin' it, no problems.

LDB

In the early years of the synthetics, there was a fair amount of scuttlebutt that to some extent group 4 (PAO-based), and especially group 5 (ester-based) synthetic oils were hard on gaskets. That may or may not have been true, as I never saw what I considered to be fully credible data in either direction. However, it is now a moot point since all full synthetic oils, even the expensive ones like Redline, Amsoil, etc, that try to imply they are pure group 4 or 5 without explicitly and illegally saying so, now contain substantial amounts of group 3 (dino oil very severely hydrocracked at over 2500psi with hydrogen). Thus, the original rationale for the problem (ie, base oils of pure group 4 or especially group 5) no longer exists.