I have an 2005 C6. My check engine oil light came up and
I took the car to the dealer. When they drained the oil they told me that I was 3.5 Qt low which is A Lot.
They opened up a couple of parts in teh engine and told me that I had not any visible leaks so they filled the car with oil and asked me to come back in 1000 miles to run an engine oil consumtion test.
So first of all I drive the car shall we say... spiritedly so I am wondering if I can consume 3.5 Qt doing that?

Secondly they OVERFILLED my engine with engine oil! ? Now my engine dip stick shows an oil mark almost 1 inch over the cross hatched area.
In the manual it says not to overfill it or the engine could be damaged... Are these guys screwing up? or could it be part of the engine consumtion test?

Has any one ever had that issue?

 

There is another thread here about inconsistencies in the dip stick measurement.

Also I changed my oil in the Z51 at 5000 miles and only drained out 4 gal. Put back 6 with the filter and it "appears" that it is overfilled. Go figure.....

 

I'm sure you mean quarts not "gal"

If I ever had that problem, I think I would check the oil more often...

 

Ya that is super weird.... What I am worried now is that It is
Overfilled showing about 3/4 of an inch over the crosshatched mark so I wonder if I shoudl take it back for them to drain it or just not worry...

 

I doubt you were 3.5 qts low. The light comes on before you are that low. How long since the last oil change? Do you ever check the oil. If the oil is 3/4" over the hash mark on the dip stick I would not do any spirited driving and take it back when they told you to. Read the owners manual and in the racing section they tell you to add 1 quart on race day. Check the oil often and if you see any foaming or bubbles take it back ASAP.

 

We'll I was pretty surprised abouty the 3.5 Qt low... the sad truth is that I bought the car from a dealership and I did not look at the oil level trusting that they were indeed selling me a certified preowned car like they were claiming (my mistake)... so I have no real way to know if the car was low on oil to begin with or if my spirited driving consumed 3.5Qt. In any event, If the manual says that if you take it racing you need to add one QT. of oil... then I should always run with on Qt extra and I should not worry about it don't you think?

Here is what the manual says:

Notice: If you use your vehicle for racing or other
competitive driving, the engine may use more
oil than it would with normal use. Low oil levels can
damage the engine. Be sure to check the oil level
often during racing or other competitive driving and
keep the level at or near 1 quart (1 L) above the
upper mark that shows the proper operating range
on the engine oil dipstick. For information on
how to add oil, see Engine Oil on page 5-14. After
the competitive driving, remove excess oil so
that the level on the dipstick is not above the upper
mark that shows the proper operating range.

Does this mean that it is OK to drive the car with more oil in the engine?

BTW, thank you all for the repplies to my questions. this is a great forum and being a member makes me as proud as being a Corvette owner.

 

NO I would not always run one extra quart. That is meant for fast corners and losing suction on the oil pump. Follow your dealers instruction. Call them and ask about the level on the dip stick. I hope the car is still under warranty.

 

Ya the car is under warranty it has only 14k miles... I (unkowingly) drove it pretty fast while on low oil so I hope no lasting damage was done and I took it to the dealer as soon as I saw the check oil level message in my DIC. After I got it back htere was no apprent loss in power that I could feel but may be I should Dyno it just to have a baseline Dyno anyway.
Given my driving I still think that I should run it with a little extra oil since sometimes fast turns do happen...

 

When my dealer or myself change the oil, it always reads 1/3 qt. above the full line.

I consume about 1 qt / 1500 miles. When I did my first oil consumption test, they drained 1/3 qt out so the dipstick would be at the full line. 1500 miles later I needed a qt of oil to bring it up to full. After the consumption test they checked the compression and leakage and said there was no problem.

A year later I started the second oil consumption test (I now have an internal engine noise). This time they changed the oil and as usual it was 1/3 qt over full. They wouldn't drain the extra 1/3 qt this time, although I had the service advisor verify that it was 1/3 qt over full.

 

If the engine is in fact, "over full" then purge out enough to get it to the "full line" on the dipstick.

A little "owner/operator due dilligence wouldn't hurt" since your butt relies on it...

You might want to check all the other stuff on your car(s) too. It can't hurt and you might learn something about your car(s).

 

one inch is one qt. If it's under one inch over, don't sweat it. Let it sit an hour on a level driveway, check the oil and measure exactly how far over it is. If it's about 1/2 to 3/4 inch or so over, it's fine. If it's over an inch over, definately get some drained out.

Check it again in 1000 miles and see how much it used. Top it off and check it again at 2000 miles, top it off then. If the two top offs in 2000 miles are more than 2 qts there may be an issue. That's when they would then do a compression and leakdown test. Hard driving, especially with a manual trans will use a little oil.

 

Thakns for the advice and the responses.

So far I have driven it for 500 miles and it went down on its own to the top of the crosshatch area of the oil stick which means that by driving it somewhat hard (shifting at 5000 RPM) I have already consumed what ever was over the limit.

What I am amazed at is that a 14k mile engine would consume oil.
I thought that This would happen to a much older engine and not a newer engine but everybody seems to have this knowledge that the car does consume engine oil if driven hard.
Where does the oil leak into? our out of? does anybody know?

 

Now you know.