Oil Change Overfill

[Boomer]

Things worked out fine! Photo from this morning.

Took my C7 in for an oil change Thurs. My regular dealer was bought out this past summer and this is the first time I had the C7 in for service with the new ownership. Drove the car the 35 miles home from the dealer with no observed issues. Took a spin on Saturday and noticed a plume of gray smoke coming from the exhaust. It was intermittent and I only saw it twice. Drove the ten miles home with that "Oh-No" feeling. The car did not overheat, temps stayed normal, no anomalous noises or performance issues and no warning lights.

Figured it had to have something to do with the oil change. Started doing my "investigation" to figure out whats up. Dipstick showed overfill. I reviewed the oil change invoice and noticed that it might have been filled with 10 quarts rather than the correct seven called for. Compared prior invoices from previous dealer and concluded the car had received 10 quarts, three more than called for which amounts to @ 45% overfill. I concluded whoever changed the oil put the Z51 amount in rather than 7 quarts for my "base".

Looking at the consequences of that and my "Oh No" feeling grew. Like a blown head gasket, a damaged cylinder head, or a cracked engine block. Called the dealer but the service shop was closed. They weren't open Sunday so I had a day and a half to figure everything out and strategy to deal with it.

So today had it towed as shown in the photo back to the dealer. They expressed genuine concern. They agreed that they had overfilled it. They checked a variety of things including the PCV and intake for oil and all looked good. They corrected the oil level by draining some and leveling it out to the correct amount. No indication of any engine damage.

Drove the 35 miles back from the dealer with a "chase" car behind me to look for exhaust smoke as I did a variety of "exercises" with the car. No prob so I'm feeling OK at this point. The car was driven 104 total miles with the 3 qt overfill.

What. if any, issues should I keep an eye out for now that might indicate a problem?

Suggestions or comments on this incident? I realize my bad for not noticing the oil amount mistake on the invoice when I paid.

[Ateupjoe]

Oh Boomer I hate to hear this story and wish I could help but I'm not that guy. But, that's one reason I'm on this forum because I know a guy or two who know a guy or two who will know what you need to know. Alright SRF members let's help out our brother here with some guidance. I'm looking to learn what folks have to say here too.

[Boomer]

It was mainly an inconvenience. Had a chance to wash it up this afternoon after its travails.

[John]

I am very sorry to hear that. The two things I would have still have checked is your MAF and your air filter, for backfill pressure potentially caused them an issue. Not a damage issue but a need to clean/replace if oil coated.

Suggest you thinking about educating your dealer or getting a new one. Five years into the C7 world, and they should now not to overfill any C7.

[Frenzy36]

Wow, Thats totally unacceptable. I would put it on a lift and make sure that none of the seals were compromised. I had the same experience with a Cadillac the dealer overfilled and the rear seal had some seepage after I removed the undercarriage coverings. I had them tow it back and they cleaned it up and said it was fine, but after about 1500 miles it developed a drip from the rear main and I had to go through hell to have them repair it. Hope you don't have any issues.

[Boomer]

Suggest you thinking about educating your dealer or getting a new one. Five years into the C7 world, and they should now not to overfill any C7.

The new ownership has instituted changes. This could be a fluke. We scheduled an oil change for the XTSvsport while we were there today.

Think I'll note the oil change amount for the XTS so I can verify it when I pay the invoice.

[Milliwatt Rob]

They don't know the difference between a dry sump and a wet sump. I am extra cautious with my Z51. One, I don't trust them to actually use Mobil 1. They may just use any Goodwrench oil, either by mistake, on purpose, or through ignorance. Second, the dry sump Z51 takes 9,8 quarts by the book.

So, I bring in my own oil, pre-measured. Its two 5 quart jugs of Pennzoil Ultra Platinum 5w-30, and I have removed 8 ounces or so from one of the jugs. I tell them its pre-measured, and to use it all. They know I am a fuss pot on such things, and they do what I ask. I let them do everything else, including the filter They charge me not much over $20 for the oil change when done this way.

[Boomer]

I don't trust them to actually use Mobil 1. They may just use any Goodwrench oil, either by mistake, on purpose, or through ignorance.

That was the other thing I questioned. There was no mention of Mobile 1 on the invoice like before and the cost per quart was a coupla bucks cheaper than what I had been charged for Mobile 1 by the prior dealer. However, they assured me it was Mobile 1 and I took their word for it. Of course, by far, my bigger concern was the overfill.

While there has been many personnel changes with the new ownership, my favorite Service Adviser is still there and I trust her. I can't imagine how she would be accountable for the overfill. Since I had figured out how it likely happened, I didn't make any inquiries as to how the service tech could make such an error. I was calm and polite throughout the process and didn't get on anybody. Hopefully the dealer has made whatever changes/training is needed to prevent such a thing from happening again.

I think I'll inquire with my favorite service adviser what actions they took as a result of the overfill. Probably see her when we take the XTSvsport in for its oil change in a week or so.

[John]

I would, as you are asking, instead, please call your SA tomorrow, and say, “we know from the earlier days of routine overfilled C7’s with dry sumps, that it most often resulted in MAF continuation of the tiny electrical wires and/or the air filter getting some oil saturation,” that you would like the soonest possible appointment to have both of those two items checked; and for her to personally either invite you back when disassembled for you to personally look at both things (as my dealership would do had they overfilled the car), or if they never allow anyone into the service area, for her to please go back at that point, takes pictures of each and show them to you.

Sorry to bring up negative things, but better safe than sorry.

[Boomer]

“we know from the earlier days of routine overfilled C7’s with dry sumps, that it most often resulted in MAF continuation of the tiny electrical wires and/or the air filter getting some oil saturation,”

Thanks John. For all I know that was done. They said a number of things were checked/inspected. The paperwork does say "Check PCV and intake for oil , none present, all good at this time". Could that have included the MAF or would that inspection indicate the MAF is OK by virtue of the PCV and intake being free of oil?

In other words could the MAF be contaminated even though no oil is present in the intake or PCV?

[John]

Thanks for the extra information Boomer. It is very positive, very good news that they checked the intake and the PCV valve and found no oil in either location, i.e., in order for the oil to have been blown back into the air cleaner, it would have had to travel backwards down the intake tube, and they noted that they found none there. When they took apart the system and checked the inside of the intake tube, the MAF was visible on the engine side where that tube connects to the motor. But while highly likely they checked the MAF at that time, it would not hurt to ask that specific question of your SA.

They could well have checked everything out when the lowered the oil level, did a thorough job of checking all needed intake components.

[Boomer]

Good info John. For my information, what happens if a MAF is contaminated with oil? What operating characteristics would result?

[John]

Good background MAF operation info.

https://en.m.wikipedia.org/wiki/Mass_flow_sensor

Info on what oil on MAF wires could cause:

https://www.fiix.io/car-advice/artic...ir-flow-sensor

[Boomer]

Terrific John. Very helpful. I went from Whatsa MAF? to knowing about it. Great forum at work!

[JB]

I104 miles isnt too many...its sounds like you caught this before it became an issue..

If upon imspection all engine seals look dry id say your ok..

id document the event...and if you are keeping that beauty longer term...

which i would recommend anyway...id get a gmepp warranty off the interweb and then offer a price match from the local dealer for his techs stupidity...

i wouldnt beat up the finance guy or owner but rather just give them the opportunity to price match it..

i usually recommend the 200 dollar deductible...and one extra year over what i anticipate myownership to be..

gm used to say an extra half or one quart on the early ls6 motors (on the ownership video tape) if you were tracking the car to prevent oil starvation ...in their wet sump systems..

two quarts over that for a hundred miles?

i dont see that as a problem...since all seals seem dry...

if you went thousands of miles youd be screwed...but 104 miles? Probably took the first ten or twenty minutes to just warm up the oil...blew out some oil past the rings for a moment on a high rev probably..you spotted it and

you got lucky and your very smart my friend...

on facebook is a world class gm tech you can ask questions...his name is Paul Koerner and his facebook name is “the corvette mechanic”

just friend him and ask the question...although id leave out your new local dealer involvement part of the story and just stay with what would happen if for 104 miles i drove a newly changed wet sump lt1 with 10 quarts of oil instead of the correct seven quarts...

Fwiw ..the dexoil the dealers are using is good oil ..I have them throw it in every couple of oil changes ..its all good if gm says so..lmo...

btw i think once or twice over the hears I added a quart of oil the dip stick said i needed but i didnt..nothing happened and i drive a ton of miles..

i think i had a little oil seepage 20k miles ago off the rear seal...we wiped it off...pit it on watch and the seepage never came back..

Im telling you guys gm builds these motors for the lowest potiential IQ ownership durability...

i love these gm engineers...they build for real,world idiot service guys,,the ones whose brains are up the butt.

they may have a motto built ford tough but GMs motto should be GM bulletproof..

i once years ago locally had a gm tech on my first corvette on my 20k mile then new c5 on a lift where he put the mounting spot of the lift on the drivers side basla wood floor...for years that floor was popped inward..used to really pis me off..then one day just banged it back down ...

i swore off idiots locally and they closed down in the 2008 debacle...i was glad to see them go..

thats why i travel to have my corvette serviced by caring and experienced corvette world class techs from then on.

i believe my gm world class tech i recommended you diplomatically ask on face book will give you things to keep an eye out for but he will probably say 104 miles you are fine ..

let us know what he says..you cam trust his insight...he is literally won an award as one of the best gm world class corvette tech awards last year at the renn center last year..

they flew him in for the award and he travels to other areas on GM s dime to properly diagnoise corvettes for gm when they have a corvette that baffles the local gm tech or regional gm manager have something they havent seen before.

and most importantly he is a sweethear of a guy..

he just loves delivering excellence inservice to corvettes...