KGrant

So if you have a car that you drive 2-3k miles a year and they manual says that you should change a minimum of once a year what do you do?

In Michigan, cars are stored generally from November - May or 6 months out the year the car just sits because of the snow. A friend asked the question and I only knew to reference what I have done for the last 16 years with my 2002 Lexus SC430 with approximately 60k miles.

In my Lexus, I would not change the oil every year but every few years when I reached the 5k oil change schedule. Never had a problem and the only maintenance on the car has only been oil change, tire and brake change and essentially that has been it. The car drives and looks like a brand new car and one of our favorites in my household.

So, the original question, would you change the C7 Z06 oil minimum once a year if you only drive it about 3k or even the 3k or 3 month schedule and just do once a year or every few years?

JJLAI724

ExRedRacer

You can't go wrong following the owner's manual. If you fail to change the oil at least once a year and if something goes wrong, you may find that GM may not honor your warranty.

$$$frumnuttin'

I am in the exact same situation....about 2-3K miles / year in SE Michigan. I am getting the warning now, but when I look at the dipstick the oil is pristine, so I am on the fence... Given that Mobil 1 is superb oil I am comfortable, as long as there is no obvious breakdown of the oil or gathering of particles or discoloration. It's all about tribology.

cowboy casey

it's all about the warranty and that is it, the oil can go between 5,000 and 10,000 miles with 0 issues but the warranty only covers 1 year... if you do not need the warranty change it when you feel like it

FunDriver

I'm getting my last free oil change next week and with my expected miles/yr I will probably hit the one-year mark before the OLM tells me to change. So I'll probably be changing once a year.

But I can certainly understand your thoughts about having to change oil without many miles on it. Maybe the one-year is pretty conservative but the manufacturer has to establish a standard for everyone to abide by so being conservative is no doubt the best choice. They might not deny a warranty for missing the mark but why chance it?

On my C5 and C6 I always used the OLM and not one-year as the time to change oil and never had a problem. In honesty I didn't know there was a one-year minimum. So I don't now what might have happened with the warranty issue if I had had an engine problem.

dashotgun

Oil gets contaminated with water which bvb turns to acid and breaks down the additives. Oil stored in a container even aged it does not have an indefinite shelf life it is a good practice to change once a year.

KillerC7zo6

My Z51 is a garage queen, 5k miles and will hit 2 years of ownership in December. I do the yearly oil change ( using my free ones )

JerryU

Oil is cheap and it's worth following the OLM! Much better than using miles.

My '93 Vette Owner's manual said:
1) Charge at 7500 miles OR ONE YEAR WHICHEVER OCCURS FIRST!
2) I f most drives are under 4 miles change at 3000 miles or 3 MONTHS WHICHEVER OCCURS FORST!

The worse thing for oil and the engine is a cold start. The extra clearance from pistons to cylinder wall and the rich fuel/air mixture required for starting and idling until the engine is warm causes combustion products to go past the rings into the crackcase.

A main product of combustion is water. It combines with the other combustion products and forms acids. Those acids corrode the metal in the engine even if you're not driving!


If the oil gets hot enough (180F) long enough it evaporates much of that water. The OLM measures the oil temp after a cold start and will decrease the time to a change if you make mostly short trips. Much better than the GM guess in '93 re using miles! So just follow the OLM even if you park the car for 6 months as those acids I the oil are corroding your engine and it needs to be changed!

Perhaps of interest the OLM uses engine revolutions as well as time. Think about it a mile on the Interstate does little harm to the engine or oil compared to miles in town with many cold starts!

SilverGhost

Why start an argument with the Owner's Manual? Unless you laugh at the prospect of the basic 3yr/36,000 mile BTB and 5yr/60,000 mile powertrain warranties being voided if you should have an engine problem, and you didn't change the oil and filter at least once a year. What does GM have to do to get the owner to change the oil, give away free oil changes?

I laughed on an '07 Z06, (the white one in my avatar), and in 2017 with 2300 miles on the odo, the DIC said the oil was just fine, the oil was still amber and not sludged, the car started just fine and ran 120 miles to the dealer to trade-in. But, YMMV.

JerryU

Hmm, you can see acids?? My '93 Vette Owner's Manual said "If most drives are under 4 miles change at 3000 miles OR 3 MONTHS, WHICHEVER OCCURES FIRST!" Bet that changed oil looks "pristine!"



Free won't help! Takes to long to get it changed!

Funny, I change the oil in the 502 cid BB Chevy in my Street Rod annually that mostly goes to local shows. I also am careful NOT to start it up to get a ladder it's blocking, pull it out of the garage and put in right back! Worse thing for the oil and engine. I try to drive ~20 miles before putting it back (and have fun) to get the oil hot and evaporate as much of the excess fuel and water as possible that passed the large cold piston to cylinder wall gaps!

If folks had assembled that Chevy Crate Engine from some 30 supplied parts as I did and saw those bare large cylinder walls and unprotected metal parts they might think about how they are corroding those metal parts with "contaminated oil" from cold starts! It's not dark sludge from "excess mileage," perhaps worse are acids that form from the water (which is a significantly product of combustion) and the other blowby.

Then again, some probably NOT!

LIStingray

You are 1 for 2.
Once a year if the car was started and run even once during the year.
All the experts, including the oil labs, recommend changing the oil before storing it for an extended time to keep the acids and contaminants from eating at the bearings - oil doesn't age just sitting in the pan.
I average 1,700-2,000 miles per year and change the oil just before the car goes into its January 1st to April 15th hibernation.

Corgidog1

I put on about 2K a year and in NJ basically do not drive on my semi regular basis till late March early April and that is when I bring it in for my annual oil change. The car really never goes into full hibernation as I will take it out if there is a nice day(s) in Jan/Feb or so with no salt on the ground. Basically that is why I change the oil in Mar/April rather than December, but yes it does make sense to change the oil before hibernation, not after.

$$$frumnuttin'

not sure which acids are being formed, and not sure if they attack bare metal....normally, it's the water that forms rust on steel and iron in the presence of air (oxygen). On a crate engine, one that's never been 'oiled' yes, no question corrosion will occur, and quickly...that is why many metal parts are shipped wrapped in special paper. On an engine already in service there has to be a thin film of lubricant on metal surfaces after use long after dormancy begins. I wonder how a dry sump factors in?

orca1946

I'm new to dry sump knowledge.

iclick

Some would consider the above as OCD behavior, but IMO Jerry is right on target about this and I do the same. My drives may only be 10 miles in summer in the C7, but winter usually takes 15 miles in S. LA to get oil up to normal temp, which I consider ~175°. I justify it as an excuse to take a nice quick ride. The 10-qts. in the C7 takes longer to heat up than the 5 qts. in my truck, which requires a shorter ride. If you don't have an OT gauge you can take a reading on the oil pan with an IR thermometer, which will get you in the ballpark. Take some readings at various ambient temps to determine how many miles it takes to get up to a reasonable OT, then just use that as your practice from then on. For me that target is 175° or higher.

My C2 service manual described it well, calling it "crankcase dilution" and warned of sulfuric acid accumulation that can result in pitted cylinder walls and pistons. I discussed this with a Mobil 1 Racing engineer a few years ago and he pointed out that oil additives are much better today, but that I should still follow the old-school practices when possible.

The short hop practice is also bad for the battery unless you keep it on a maintainer.

Kenny94945

Once a year is the answer.

Cost $100 for an oil change.

With a Blackstone Lab report, maybe one could extend the time, but 1 year is the answer.

vader86

Once a year regardless of how little you drive it.

JerryU

Thanks for answering the “what acid!” I can assure “$$$frumnuttin'” acid be it nitric or sulfuric will corrode metal much faster than water. We used both to clean welding rod before drawing to size! Then used a neutralizing bath than finished with water to wash all that “stuff” off. Water was the least corrosive.

Yep a thin film of oil should cover most parts but one preferably without acids! We did use a product called "vapor paper" on steel wire for protection. However for aluminum wire after is was "double shaved" to eliminate all oxide and surface defects it protected itself with a thin oxide layer.

In the met lab we used a mixture of acids on a polished surface that brought out the grain structure in seconds. Had to quickly wash it off with alcohol!

JK 23112

My 2017 Stingray (non-Z51) has the "wet sump" oil system (like any regular car) and it is mostly a garage queen. I drove it home brand-new on February 1st of 2017 and had the first "free" oil change done at 3,000 miles in June of 2017. My OLM said I still had just under 40 percent remaining, but I wanted to change it out and had a day off work when they could give me an appointment at the Chevy dealership.

I drove it a few times during "warmer" days last winter and had the oil changed again two weeks ago at 5,800 miles. The OLM was on 30 percent - probably because nearly a year had passed even though I only drove 2,800 miles since the first oil change. The oil on the dipstick was barely dirty at all (same as last time), but a year is still a year and I have always been **** about vehicle maintenance.

When I had my second "free" oil change done, the service writer said that all 2017 Corvettes get THREE oil & filter changes, even the wet-sump ones like mine. He said the computer system apparently does not know which cars are which (I thought the VIN would differentiate them somehow), so a glitch by GM gave me three instead of just two (and my car doesn't require the 500-mile change the way it does for the dry-sump Corvettes).

I'll get my last one done before the winter weather hits again - and should have some more miles on it by the end of the season. I have 6,300 on it now (did a lot of driving last week with a nice road trip) and will likely hit 9,000 to 10,000 by the end of the year. I'll be ready for my third (and final) "free" oil change by then. So long as we get them done BEFORE the two-year date of ownership, GM foots the bill. I have until 2-1-19 to knock that one out. Next summer, I'll have to do it myself (with the ramps, jack, etc., etc.).

FWIW, I was told that I cannot rotate the tires on my Stingray - even though a service is supposed to include that. As is the case with every C7, the tires & wheels on the rear are larger than those on the front. I suppose getting 20 to 25k miles out of a set of the OEM tires is doing pretty well. Better save up a few bucks, eh? I figure that with the low miles, I can get at least four years out of my first set if I continue to drive it decently.

With oil, you should always err on the side of caution - especially if the car is still under factory warranty. Oil is the lifeblood of your engine and changing it more often than necessary is just 'cheap insurance' and peace of mind for any car enthusiast. Heck, I changed it at 3,700 miles on my 2018 Honda Accord (my DD) and will do it again by 7,500 - even though I could go a lot longer. As with the 'Vette, the new Accord calls for Mobil-1 synthetic, but in a different viscosity.

Save the wave!!