theroar

I'm interested to know why I should change the oil after the first 500 mi. In my C7 LT 1. I'm no mechanic but seems like over kill to me.

thirtythird

Something about dry sump cars whereby some silicone seals may initially break down the anti-foaming properties of the oil.

silver74vette

Because the chemicals used in the assembly process and given off by the sealants used can cause issues. Not to mention it is beneficial to remove the wear products from break-in.

silver74vette

You beat me to it.

mountainears

It is only for vehicles equipped with the dry sump and it was a change that was released to the process a little time after they started shipping them, so they saw something to recommend the change.

It is included / free, on top of the other two free ones you get.

It's on page 308 of the manual where it calls it out, and there are service bulletins out there for the dealers as well that have been published in these forums.

DCortez

I'm a dinosaur that changes out at 500 miles on every vehicle.

l2vette

Your not alone!!

ersatz928

Me too...and then I will be changing the oil and filter every 3000 miles after that....like I do on all my cars....

Jeffthunbird

Only on dry sump, correct? I didn't think this applied ton Non Z51 Stingray.

alexsoo

I took the oil cap off while the engine was running. Looked inside the dry sump tank and it was like a bubble bath Needless to say I told it in at 600miles to get the oil changed. I should look into the tank with the new oil when I get a chance.

JK 23112

The 500-mile oil change is ONLY for the Z51/dry sump oil systems.

ersatz928

Because the silicone leaches out of the seals used in the dry sump system, which degrades the anti-foaming additive of the oil.

JerryU

This is a more technical explanation and also a warning at the end!
I have a September 2013 built Z51. GM did not issue the bulletin to change dry sumps at 500 miles until 13 months after I got mine! I was concerned since I did not change my oil until 1500 miles. In fact dealers were not changing free until the OLM said 20% or less in 2013! I change my own-Free is not worth it IMO-see below.

These are the key points from that GM Bulletin:

GM Bulletin issued 11/24/2014
Dry sumps engines may experience oil leaking from air cleaner---This condition may be caused by running the engine continuously at sustained high speeds with the first factory fill---resulting in silicone sealant gaskets degrading the antifoam agents…… The oil foam has no effect on engine durability.


Note the issue is oil foam forming because of depleted antifoam agents from curing silicone seals. Apparently you have to wait for ~500 miles as the engine operates hot to have all the silicone enter the 1st oil fill. It's NOT really break-in oil it's standard Mobil 1. Wet sumps don't have to let air "burp" from the dry sump tank as they don't have one, therefore any foam formed does no harm. They don't have to change at 500 miles nor will GM pay for that extra change.

WARNING
From observations of C7 forum posts in over 3 years it appears to me that "running the engine continuously at sustained high speeds with the first factory fill," has little to do with oil dripping from the air filter. Doubt there are many folks who do that!

Oil dripping is still reported by folks who change oil at 500 miles, often right after their "Free" oil change!

Some mechanics helpers who often work the oil change bay overfill dry sumps! IMO that is an has been the real oil dripping problem!

Read the Owner's Manual it is more difficult to check oil level with a dry sump. IMO some of these dealer "oil changers" don't take the time-they just set a volume number and pump oil from the 55 gallon drum in the bay. (That may also be at those dealers who give folks a hard time about using Mobil 1! They want to use the cheap dexos approved blend in those 55 gallon drums NOT quarts of more expensive Mobil 1!)

The Service Manual clearly says that the oil volume in a chart is only an estimate of what is needed. You must check the oil level. (That is what I have done in over 50 years of changing oil-it's the level that is important NOT the volume.) In a dry sump that means getting the oil hot, >175F. That takes ~10 minutes at idle. Then, using a watch, wait 5 minutes as the oil drains down from the dry sump tank internal baffles and walls. But they can't just go for coffee as you can NOT wait more than 10 minutes or you'll get a false low reading! Oil drains back from the tank to the pan past the scavenge pump gears so checks MUST be made before 10 minutes.

For a wet sump they can change oil in minutes not ~1/2 our removing two drain plugs waiting for the oil to drain from the dry sump tank through hoses while all is out then get it hot and wait to check-but not too long!

Lots of complaints about overfilling! Many of us change our own and that is one reason. Here is a suggestion if you are having the dealer make the change. Ask the dealer to only put in 9 quarts and give you the 10th quart. When you get home check the level and add until it's half way between Fill and MAX lines. You'll probably need less than 1/2 quart. If they object, then before you leave the dealership get the oil hot and check yourself. If over the MAX level don't drive and complain! You have to learn how to check oil level-practice before you bring it in! FWIW

Foosh

A long read, but Jerry is dead-on, completely accurate above!

sdurg24

Which includes every Grand Sport, a fact that some are not aware of.

JerryU

Good point! Because some may like the GS look and the price is not much more than the base car I forgot they might buy one without knowing!

Reminding me of the Z51 value when I got mine, $2800! Could not believe I was getting a dry sump, manual trans and differential cooler, HD springs, 45 mm HD shocks, added rear sway bar, eLSD rear activated with a 3000 psi hydraulic pump, larger brakes, bigger wheel and tires and an added spoiler for that price. About half the cars sold had the Z51 option.

Some folks got the option just for the wheels/tires and spoiler! Actually not a bad price just for those! Then they found out it was more difficult to check oil level. Recall one fellow who said, "I'm not going to use a watch to check oil." He will if he was going to get a proper reading.

Others were then complaining about the terrible brake dust and the increased "chatter" on slow speed full lock turns when cold.

Wonder how many GS owners do not know they will have to change to ceramic brake pads to get rid of the dust problem! I was cleaning my black wheels every two trips to town (~100 miles in total) or they looked bad and caused pitting! Even though I bought the Z51 strictly for performance I changed to ceramic pads! Solves the dust and pitting issue (just not for tracking.)

theroar

Thanks for bringing that to my attention. Reread that page.....a lot to take in in the owners manual.

jaybar

I've had a c-4, and a c-5 I replaced the engine with a LS-6 crate engine. Took that car to a tuner after a few hundred miles to ran it to redline on a dyno to adjust the air/fuel etc.

Now I have a c-7 Grand Sport on order and will pick it up at a dealer 1,000 miles from home. I have never worried about break in's in the past but from all the talk on this forum I have some questions.
One is it ok to run at constant highway speeds for 18 hours (may split the trip over two days)?
And I will miss the 500 mile oil change by 500 miles.

So am I in trouble from the get-go?

If the 500 mile oil change is a deal breaker I guess I could find a Jiffy lube along the way but do not have a good feeling about using them for my first service.

Any suggustions?

L8ter

You might want to stay on the back roads for the first few hundred miles. Change gears often, and fluctuate your rpms.
Maybe able to find a dealer along the way to do your first oil change. Preferably a larger one who sells a good number of Vettes.

dbaker

Had mine done on Tues.507 miles.

Dealer put in 9 qts as I requested and took the 10th qt home to top off.Car was NOT put on a lift but rather they used a drive on service ramp.

Good job by Burns Chevy in Rock Hill,SC

\db2