Grand Sport Oil Overfill Question
 

I recently took my 2018 Grand Sport to a Chevy dealership for the 500 mile oil change.

After I got it home I checked the oil level and it was overfilled (above the hash marks and twist). I called the dealership and scheduled an appointment the next day to have it corrected.

I took the car in and told them it was overfilled. The adviser looked at the system and said it seemed like they put 10 qts in when they should have only put 9.8 in. They pulled the car around to fix the issue. While a I was waiting, my wife called and told me there was a large pool of oil on the garage floor. I let my adviser know and we went out to talk to the tech that was working on my car. They lifted it up so we could take a better look and sure enough there was oil all over the underside. He wasn't sure where it was coming from but they cleaned it up, corrected the overfill and told me to keep an eye on it.

Once I got home I checked the oil again and it was at or slightly above the hash mark. A little bit later I checked under the car and sure enough it was leaking more oil. I called the dealer again to set up another appointment. I also decided to check the air filter to see if oil had gotten in there and was greeted to this:

https://cimg9.ibsrv.net/gimg/www.cor...b08038af5a.jpgOil on air filter.
https://cimg0.ibsrv.net/gimg/www.cor...be0d506f92.jpgOil pooled in air intake.
https://cimg1.ibsrv.net/gimg/www.cor...a62c3ebdb8.jpgThrottle body intake.
Now I'm not sure what to do. The car has not thrown any codes but I'm not sure if the oil has caused any lasting damage yet.

If I clean things up is it safe to drive? Or should I have it transported to the dealership?

I would appreciate any advice people could provide. Thanks.

When the dry sump system is overfilled, the oil burps out of the oil tank into the air hose that runs from the tank to the clean air side of the air intake, just behind the air filter. The oil pools in the air filter box and leaks out of the bottom of the air box, onto the belly pan and onto your garage floor. Oil spray is also drawn into the whole engine air intake system coating and pooling in various areas of the intake plumbing. Disassemble the entire plastic intake pathway from the air filter to the throttle body and clean all internal components. Turn the removed pieces in all directions to drain oil that has been captured in the nooks and crannies or the intake plumbing. Clean everything below the air filter where the oil leaked out of the air filter box. Remove and clean the belly pan. Blow oil out of the air hose the runs from the top of the oil tank to the air box. Remove excess oil with a turkey baster from the oil tank. Reassemble everything, using a new, uncontaminated air filer. Now you're good to go... and in the future, change your own oil! No lasting damage done.

Al Engel "Save the Wave"

You'll probably get a better response from someone else, but this is my guess at what's happening. I'm guessing they're filling it to full spec right away. They should fill it with 9, warm it up, then check it after 5 minutes. I suspect they're putting in the full 9.8 running it, and checking it right away. Some folks ask the dealer to put in 9, take one home, and finish the fill themselves.

It's amazing how many chevy dealers don't know how to properly service the dry sump system.

Living in the DFW area you've got plenty of dealerships in the area that are Corvette-savvy. IMO your dealer filled the dry sump just like a wet sump engine, not once, but TWICE.

I'd take it to a dealership with a reputation for servicing the dry sump C6 and C7s. OR tell you dealer to service the engine to 9 quarts ONLY, and give you the extra quart.

BTW, when I changed the air filter on my '14 right after I bought it, the air intake had oil puddled, so I feel your pain. Since I filled it myself, everything's stayed dry.

HTH, and have a good one,
Mike

My guess is they put more than 10 quarts if the level was above the twisty part of the dipstick.
I run mine with the oil at the top of the Hash Mark.
I've also put 10 quarts before and it's barely above the Hash Mark.
And that's checking Correctly between 5-10 minutes with the engine Temp 175 temp or above.

When I asked the SW at the last dealer who changed my oil to install 9 qts. and hold one for me to top off later he balked at first, then said "Okay, because if we do it we'll either use 9 or 10 qts., no partials." Thus, 9.8=10 to them. I keep mine at halfway up the hash marks, which is 9.5 qts. That's all it needs, and no barfing of oil in places not meant to be barfed in. Also, I check it only at 175° OT after the engine has been off for 7 min., and in the same place every time (my garage).

All that said I can't believe overfilling 0.2 qts. would hurt anything, so I assume the OP's dealer overfilled his sump more than that. If using 10 qts. would cause even the slightest damage of any kind I would think there would be some sort of warning in the user manual, and I see none.

Thanks for the help. I just had a follow up question on what the belly pan is. Is this the large plastic piece that is under the radiator fan and in front of the cross member? I certainly see oil pooled there but just wanted to make sure I don't miss anything else.

I agree with that as there was definitely more than 0.2 qts between the floor and the engine compartment.

This has happened repeatedly to a lot of people, and the easy solution is to only allow a dealer to put 9 qts. in and provide you the 10th qt. to take home and adjust the level later. I've done 4 oil changes this way, the dealer has no problem complying with my request, and every single time, the oil level is exactly in the middle of the two hash marks w/ just 9 qts. That's where I leave it.

Yes... I call the flat plastic part below the radiator - air box the 'belly pan'. The GM Parts guys have a more technical name for it... the "Front Bumper Facia Air Deflector". I like "belly pan" better.

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Al Engel "Save the Wave"

I agree, 9 quarts is definitely the way to go.
I was wondering if anyone has had kick-back from the dealer in honoring their 9-quart fill request?
Considering the attitude of some of these dealers, I can imagine, them playing "we only perform work to GM specification" card.

9.8 qts, to me doesn't fit standard measure metrics of design, Car manufactures when designing vehicles appear to make it user friendly for the driver to be able to refill fluids and or checking fluid levels. Be it, washer fluid, oil,etc. In turn this becomes a topic of discussion (what if) about extra .2 qts is added. I think GM should of designed it for whole number of quarts, making it a no brainer for GM oil tech and or us. Theory is not all oil is removed when draining oil,maybe that's why GM says 9.8 qts.

Maybe they only opened ONE of the drain plugs and then put in the 10 quarts.

I wouldn't be surprised if that was the case on the first trip. The tech I spoke to on the second trip was aware of both drain plugs and that it was a dry sump system. I just wish they would have looked a little harder to find the source of the oil leak.

:iagree: IMO, from reading many forum posts there is more of a chance for oil dripping from the air filter having a dealer change oil then the reason for the 500 mile change causing what it is designed to prevent - the same thing! That is all it is designed to do per the Bulletin!

The GM bulletin that required changing at 500 miles (that came out 13months after I got my Z51 dry sump) said that oil dripping from the air filter MAY occur IF the engine is operated at SUSTAINED HIGH SPED!

Second: The 2014 4 volume Service Manual clearly says how to fill the oil and states the chart is only an estimate. You must check the level and fill to the proper level BUT that 9.8 is only an estimate. I changed oil with my Dad from when I was ~10 years old. If I ever filled to some volume estimate I would have been "corrected!" It is the level that is important NOT some volume in a table! Even in a wet sump excess oil can hit the spinning crack an cause oil foaming! Some Owner's Manuals clearly say overfilling is as bad as being too low.

Many of us fill our dry sumps half way between Min and Max! That is a half quart over Min. The manual clearly says add one quart if at the MIN level. It does NOT say the oil needs to be at MAX.
Your car do as you wish!

I do all my own oil changes, did on my 2014 Z51 and now my Grand Sport. I know it's done right! I have my car level when it drains and wait until all oil has dripped from both plugs. I add 9 quarts then check. I am adding less than an extra half quart to get it half way, so 9.8 quarts will put it over the full mark. Not a lot but over.

If you trust the dealer will: 1) use Mobil 1 oil, 2) lift your car and NOT crack your rocker panels, 3) properly tighten the oil filter and 4) not overtighten the drain plugs then as others suggest have them fill with 9 quarts and give you the 10th! Check when you get home when the oil is hot and frankly it is easier to see when it mixes with the residual left in the rocker arms, pockets in the head etc.

If they refuse to fill with 9 and give you the 10th quart, as some have say has happened, that may be because the they are filling with the Oh-So-Peachy oil blend they have in the oil change bay in 55 gallon drums that meets the GM dexos spec that they bought from the low cost supplier! Then that mechanics helper, who might have been flipping burgers a few weeks before, can just pull the handle on a pump gun and not have to go to the parts department to get 10 quarts of Mobil 1 and lug those back to the oil change service bay! :lol:

Frankly with that much oil dripping, I would be concerned about contamination of the MAF sensor that is a few inches in front of the air filter in the air intake tube. It sends a signal to the computer that controls the air/fuel ratio. That problem could occur sometime after the filter replacement!

Some report the dealer did replace it after an incident of overfilling and wet filter! That would be on their dime as GM IS NOT GOING TO reimburse them for a mistake!

I would insist that it be replaced as some have had done!

FUNNY:
A few folks have commented that my use of an oiled cotton filter in my aFe will cause a problem. It could IF it's not oiled properly. In fact aFe has a dry replaceable filter option for those who don't know how to do it properly! The new GM low restriction air intake system uses a dry filter, replicable not cleanable filter as well.

The amount of oil on the cotton filter as received cannot be felt! I have used K&N oiled cotton filters for years and know now to not over oil. Have never had an issue with the MAF for cars that had them. Just takes knowing now to lightly oil and let it spread, which takes some time. An oil soaked paper filter can easily cause an MAF sensor malfunction, if not right away in time.

When I had my 500 mile oil change, I asked the service mgr. to put in 9 qt. and give me the 10th. He said he couldn't do it that way, because they have Mobil 1 in bulk. They put 9.2 qt. in the engine and when I got home I properly checked and it was filled to the max line on the dipstick. I also checked out the GM part number for the oil used and it was for Mobil 1 in bulk. For the second oil change they put in 9.8 qt. I was surprised because it was more than the first time. I properly checked the oil level when I got home and it was 3/8" higher than the max line. I immediately took it back to the dealership and they changed the oil a second time. They didn't tell me how much they added, but commented that there was some confusion about the proper amount of oil to add. I checked when I got home and the oil level was right at the max line.

FWIW:
The volume is NOT IMPORTANT IT'S THE OIL LEVEL!
This is what it says in the 2014 Service Manual, quoting:
Page 1-36 OF 4 Volume Manual
Approximate Fluid Capacities:
"When adding, be sure to fill to the approximate level, as recommended in this manual (table is the same as in Owner's Manual.) Recheck fluid level after filling."

To check a dry sump the oil needs to be hot and must be checked using a watch after 5 but before 10 minutes after shutting the engine off. All takes too long for many mechanics! Wait more than 10 minutes and oil will drain back to the pan and you'll get a false low reading! Wonder how many mechanic's helpers know that? Take a coffee break and measure after 30 minutes and it will read low and then you would overfill to get it to the MAX level. For fun I checked my oil before starting the car one morning and it was below the oil dip stick tip >5 quarts low!

FUN STORY ABOUT THE 502 CID ENGINE IN MY STREET ROD:
Have a wet sump Chevy crate engine in my ’34 Ford street rod. First, even in a wet sump it is NOT the volume of oil that it critical, it's the oil level. The key is you don’t want the oil level in the pan to be close to the 6000 rpm rotating crack causing foam, drag etc. To have access to the dip stick with my large diameter long tube headers I bought a billet aluminum knob Lokar dip stick. It comes with a universal flexible dip stick that must be cut to the proper length. No problem, I thought, just check with the initial fill of oil!

Except here is what GM says is the required amount of fill: “After installing the engine, ensure the crankcase has been filled with 5W30 motor oil (non-synthetic) to the recommended oil fill level on the dipstick!” The engine instructions say nothing about an oil volume, not even and estimate! Just fill to the proper level.

But the dip stick the OEM tube has to be installed-it does not fit with the long tube headers. A Catch 22! Had to cut the top off the steel OEM dip stick and make measurements of the dip stick tube length and then fill with oil! Then I could cut the Lokar flexible dip stick to the proper length!