Ramler

Time is not a concern for me, I put way more than 5,00 a year. Cars are made to be driven. The next owner is just out of luck.

joemessman

Do exactly as the manual states. Believe me. The people that wrote the manual know what they are doing.

LT1 Z51

While I get what you are trying to say (and can appreciate the logic), this could not be further from the truth.

The Owners Manual is literally written by marketing and legal with some input from engineering. The Service Manual is written mostly by sales and service, again with some input by engineering.

Engineers for the most part hate documenting or writing things, they always want to be "doing" things and solving problems. Proofreading and approving the sections of the Owners Manual and Service Manual are the lowest priority unless they have to do with closing out a specific topic (like preventing future recalls, or unnecessary warranty work).

They are literally the least cared about documents, and are riddled with errors (the 2014 manual being different than 2015+ is likely due to an error).

Of course there are people here who take those documents as gospel and put them on level footing with the bible.

BlueFinn

Assuming one puts 0 or very low mileage on the vette in one year. What is happening to the oil sitting in the engine during the year to require that it be changed?

I am not suggesting the engine oil not be changed, just wondering how it would deteriorate? Why is that different from oil sitting in a can on the shelf for longer than one year?
John

LT1 Z51

Supposedly moisture enters the oil causing many additives to break down or lose effectiveness.

The rate at which this happens is the reason for the debate on if oil should be changed yearly, every other year or longer.

There doesn't seem to be a disagreement on if oil goes "bad" just when.

Walt White Coupe

Of course there are people here who take those documents as gospel and put them on level footing with the bible.

And then there are people like you that don't believe anything but their own misconceptions.

LT1 Z51

It's not a misconception but rather personal industry experience. If you don't want to take my word for it that's fine, but when it comes to what goes on in automotive I have more experience than the majority of this forum (including yourself). If that experience doesn't mean anything to you, fine, but the truth is the truth and you can feel free to ignore it.

Regardless there is no need to insult me because I challenge people.

Foosh

Walt,

He is an engineer for a major US vehicle manufacturer. Plus, what he says is true regarding frequent poorly written manuals, as well as inaccuracies.

Walt White Coupe

The idea that engineers input take back seat to "sales & service" is just baloney. Nothing that man does is 100% perfect, manuals included.

And for: Engineers for the most part hate documenting or writing things, they always want to be "doing" things and solving problems.

More balooney. How do you solve problems if you don't document what you have found? You wouldn't have a job very long.

LT1 Z51

In my experience in automotive, and this is going across Ford, GM, and Chrysler documentation is lacking in many many aspects. Where there is documentation it is often sub-par and riddled with errors (or out of date information). Requirements and Specifications included.

Engineers are overworked in many respects, the amount of unread e-mails in peoples inboxes is 100+ (due to the sheer amount of crap which gets sent daily). I'm one of the few people I know who keeps a tight lid on his e-mail, the others like me tend to be younger (and I think we all check our e-mails when not at work anyway, or insta delete the "junk ones").

Automotive is not keen on doing things other than "one pager" power points, or 5D's or 8D's. Outside of management meetings (which consist of power point presentations and the above documents) there are very few meetings which actually generate "minutes" and this is mostly because many of the meetings are more "informal" and problem solving than actually documenting things.

Plants want to build cars, you need to be there on the ground boots in the **** getting things done. If you are LUCKY you have time afterward to document what you did in detail. Typically you don't, most of the institutional knowledge in the industry is contained within the people, when you lose someone to another employer you lose information, sometimes permanently.

My job is actually to write requirements, as you can all gather I like to write, I like to talk. I'm rare in this regard, and so I'm one of the few people who actually enjoys this, most other people don't. Don't even get me started on people who do models, or write code. In my last job the software processes were lacking and even the ones that existed didn't get followed.

Automotive is for the most the wild wild west.

BaconWrappedSushi

Interesting discussion. I've worked in the IT field on and off at my employer and I can tell you that dealing with them documentation is an afterthought. The problem is, and I'm sure engineers is the exact same thing, whenever you complete one thing, you don't have time to document anything because you need to start your next project.

Combine that with leaders having to constantly meet with PMs (Project Managers) to update them on their potential progress versus actually working, then presenting at a steering committee... you can easily see the time for accurate documentation going away.

I would not say that discredits the user manual, but would instead just caution using common sense in combination with the literature in the manual. If you are concerned about the oil OP, just change it and the peace of mind is worth it. Personally for me, I'm letting it run to <10% because I have ran my intervals long in all my cars and have yet to have any sort of engine problems that are oil based.

JerryU

Both statements could be correct!

Managed a number of engineers in an R&D lab! Some of our most creative, who developed new products and had a number of patents, hated details. I just gave the detailed tasks of writing instruction literature and working to implement new products with several plants to other engineers who were detailed oriented! Both were happy as were customers/plant folk who had to read and understand the info!

My boss managed four R&D facilities and was a brilliant physicist who invented plasma cutting/welding. He insisted our monthly Lab reports be well written and easy to follow. My summary was! Fortunately he was at corporate headquarters in NYC and only visited our OH Lab every ~6 weeks. He could stress the staff!

Patman

I trust the OLM in Corvettes for a couple of reasons. Number one is the fact that my C5 had 133,000 miles on it when I traded it in, and I followed the oil life monitor for every oil change (I even went longer a few times too) I also had an oil analysis done on every oil change too, just to make sure the oil was still doing it's job (it was). The LS1 in that car ran great and burned less oil than many other LS1s out there. I also remember another member here with a C5 who had over 400k on his car and followed the OLM for every oil change. You can't argue with that one.

The fact that GM now has added the time factor to the OLM makes it even more safe, as most people with Corvettes will hit the one year time limit first, and the amount of miles on the oil will not be the determining factor. But even if it was, GM has put a lot of work into the OLM, long time members here might remember there was a member who was part of the team that helped develop the OLM in the C5, and they didn't just slap that thing together in a day. A lot of research went into it.

mschuyler

Who cares? The issue is when to change your oil. The answer is, change the oil when the car tells you to until it's out of warranty, then do the hell what you want. That preserves your warranty. We ought to change the title of this section to "How to make mountains out of mole hills."

LT1 Z51

All threads about Tires and Oils always turn into mountains. That's life.

C6_Racer_X

It should go another 500 miles of "road trip" driving.

You definitely want to get it changed before it gets down to 0%, and it will start nagging around 5%.

Will you be changing it yourself? A friend changing it for you? Or will you be taking in in to a dealership? Or a "corvette specialty" shop?

JerryU

There is an "Oil Expert" who occasionally posts. His logic for changing with time is why I do it even in my street rod that mostly goes to shows. Not just that the instructions that came with the Chevy crate motor said to!

Every time the car is started you get extra blowby from cold pistons having more clearance. That blowby mixes with the oil and forms acids. It's particularly and issue with its large forged pistons in the street rod. Can hear piston slap until it warms up! The air/fuel mixture is richer on startup so all the fuel is not combusted. Worst with the Holley in my street rod than with computer controlled fuel injection but still an issue.

I even try not to start the engine if I am not going to get the oil hot! Worse thing for some garage queens is pulling it out of the garage to get something it's blocking and pulling it right back in! The OLM takes into consideration the number of starts, not getting the oil hot enough long enough to evaporate some of the water from combustion etc.

joemessman

I do know this. I stick to the oil life monitor, which prompts me at about 7,500 miles. I have 44,000 miles on the car and doesn't burn one drop of oil. When I take it in for the oil change it is right up at the top mark right where they filled to at the previous oil change. And I really drive the **** out of this car! I'm surprised I still have a usable floor board.

JerryU

^^^

cls33

Slight derail... where are most of you getting oil changes done at? Dealership? Neighborhood mechanic? DIY?

And if you're not doing it yourself, what's the going rate for a C7 mobile 1 oil change?