Low oil light (scary experience) please advise
 

I had a scarry but interesting experience the other day. I was not really aware that i should check the oil level every 1000 miles so i did not but more was focused on the oil life gauge. I have the Z51, LT3.
2 days back i started hearing a valve chatter in the morning start up and then that afternoon my low oil pressure light came on. I dont think it was my low oil light but the low oil pressure.
I pulled over and checked the oil level and showed no oil on the dip stick.
Long story short i was down 7 quarts!!!! and even after the 7th quart it was still not full. I went to the dealer and said, depending on the driving it burns a quart every 1000.

My question is why didnt my low oil light come on after down 2 quarts as with my C5 it always let me know when low. I cant believe my engine did not blow up!!!
dave

I think your service writer is full of chit. In my mind any new car that burns a quart of oil in 1000 miles is broke. BTW. check for leaks, and always check your oil regularly.:) If it keeps burning that much oil I suggest another dealer that has Tech's with some common sense.

Agree with Rebel. Neither of my C7 LT1 dry sumps required any oil added at all between changes, about 4500 miles for the way I drive. At most, they were 1/2 quart low when the oil was changed.

Something isn't right, and I'm wondering if it was filled properly at the last oil change. Good luck and I hope you have no permanent damage, but I'd be very concerned.

When was the oil last changed and who did the work? If it was a dealer, it is very likely that they did not fill it up to begin with. If it was consuming that much oil, you would be smoking like a freight train...

Amen to that ! no way that car should be burning 1 quart of oil for every 1000 miles, that's ridiculous. The only way that happens is if there's something wrong with the car, leak, bad piston rings or you have a couple of hundred thousand miles on it.

Was changed at the dealer 3000 ago

No smoke at all

Since this is Z51 with the dry sump do you know the correct proceeding for the checking the oil? It requires the car to be run up to operation temperature then wait 5 to 10 minutes before checking the oil level. If you checked when cold it would read nothing on the dip stick.

Did you check the level before you left the dealership when they last changed it? If not, you need to start doing so because they have also been known to overfill the dry sump system. Another option and one that I live by is to change it yourself.

If no leaks it sounds like it was not filled properly at your last oil change. I change every 7,500 or so, and never burn a drop according to my dip stick. And yes.....if it was burning oil to the tune of 5 quarts or so in 3,000 miles from your last change you would have noticed smoke at one time or another. Me thinks the dealer who last changed your oil has some splaining to do!
I know this is of no help now, but I'm one of those that checks the oil level every day before I take the car out for a drive, as well as tire pressure.
Hope no damage done. Will have positive thoughts for you and your car. :thumbs:

You need to find another dealer ASAP with a qualified Corvette tech who knows what they are talking about. No way should a car burn a quart of oil every 1k miles. In your case to go through 7+ quarts in 3k miles indicates you have a serious problem.

Thanks, i dont know where the oil is going if its not burning. No leak, no smoke!

Do you have any evidence that the oil was ever filled to the proper level between the last oil change and when the oil pressure light came on?

wait there's a dipstick?

wait there's a hood latch?

wait, there's oil??

Dipstick can be found at the dealership service department...

Nope, only a trunk latch...

Nope, it's a sealed system...no oil required

my '88 F-150 burned 2 quarts between changes, ford said it was normal. I sold it.
for 45 years I've changed oil in vehicles. I almost always drain 9/10's of Fill. (i usually measure it).
you either have an engine problem, or a prior-technician-problem which has caused an engine problem.

Now that made me laugh.......:rofl:

Dave, if you didn't, do as lake says. Oil checks for the dry sump engine is counter to any oil checks I've ever done. Warn it up, then check. And, for goodness sake make sure you put the oil in the correct hole, don't mistake the surge tank cap for the oil cap. You may not think so, but that has happened before.

no but it was the chevy dealer and i do trust them but who knows!

i didnot check

I'm not sure that there is a low oil light on the dry sump. The C6 dry sump didn't have any way to measure oil level (unlike the wet sump), and I'm assuming that the C7 dry sump is the same, so no warning light.

I've spent too much time on here reading about dealership service departments not getting it right with oil changes so you cannot trust them. I personally experienced an overfill condition when I purchased mine so it's pretty common primarily because the dry sump requires a different procedure to check the level and they end up overfilling. This is the first time I've heard of them under filling, but perhaps in the midst of filling the oil, they got a text message, meal truck showed up, or something else happened to distract them and it never got topped off. Thank goodness it at least had a couple quarts in it otherwise, we would be discussing the following topic: "My Engine Locked Up While Leaving the Dealership After An Oil Change"

Yes i was really worried on the side of the road! Actually sick to my stomach. This is actually a new engine install. Its a 2014 and the original engine had unfixable valve issue and GM changed it with a 2017 new engine. I read the car fax report and said cost $19,500.00.

I wonder why they got rid of the low oil level sensor on the C6 and on the C7? I know that my C5 had a low oil level sensor in it (it would trigger when you were about 1.5 quarts low though, but that's better than nothing)

^^^
This

Be sure you didn't overfill it. At shutdown the dipstick will show no oil with a dry sump.

The C6 wet sump still has the oil level sensor. It triggers at about the same point.

I guess my wording was not clear enough.

I'm assuming your C5 was a wet sump?

There is no low oil sensor or light on the dry sump engine cars. Because of the nature of the dry sump there is a wide variance in the expected oil level in the storage tank depending upon operating conditions so unlike the wet sump cars there is no overall typical level when the engine is operating.

Although it is important to check oil level frequently to gauge usage among other reasons, with the dry sump system it is even more important. I suspect one reason the Cadillac CTS-V version of the LT-4 used a wet sump was to avoid this procedure which is difficult for some owners and Cadillac rightly assumes that many typical Cadillac buyers would not be happy with the dry sump level check procedure.

thank you
dave

I am guessing the dealer "tech" gave it a wet sump fill of only 7 quarts. Regardless, check your oil frequently. I do so on my entire stable at least once per week. I still do my own oil changes (except on my wife's BMW with no dipstick). The last time I let a dealer do the change on a new car (other than a BMW) was a new 2010 Ford Fusion. It came with 3 free oil changes so when it came time for the first oil change I said, "what the heck, what could go wrong." Well I got it home and checked the oil. Barely showed at the bottom of the dipstick. Took almost 2 quarts on a 4 cylinder to get it to the full line. Turns out the quick lane supervisor did the change. The service manager offered me 3 additional free oil changes for the error. I said "Not a chance. I am not going to give you any more opportunities to screw up my engine."

There was no dry sump setup on the C5, that didn't come out until the introduction of the C6 Grand Sport. I never realized that the C6 wet sump had an oil level sensor, for some reason I thought they didn't have one.

^^^^My money's on this

OP said it was 7 qts low so if that's the case it now has 14 qts in it. Not sure 14 qts would physically fit...

Once I joined up here and read the horror stories about the dry sump I decided to do my own oil changes. Too much confusion, not worth the risk. You would hope a Chevy dealership wouldn’t screw this up but honestly they don’t pay the techs anymore to work on Vette vs a Cruze.

As others have posted, the (almost) foolproof way to get the proper dry-sump level at change is to have the dealer put in 9 qts and give you the 10th qt to top off at home, because the system holds about 9.8
Buy a funnel for the at-home part.

If they use the slightly older 1 liter bottles instead of quarts, you'll be almost at full.

Unfortunately, the dealer can still screw up if they fail to pull both drain plugs on the dry sump, that causes an overfill.

Our Owner Manual says to warm the oil to 175', shut down, wait 5-10 minutes, and then check level in the tank.

The C7 Z06 had the dry sump LS7, when it was introduced in the 2006 MY.

Back to the point and as I said in post #3, about the only way OP could have ended up so under-filled is that the tech got distracted and didn't fill it properly at the last oil change, or it leaked out. The latter has apparently been ruled out by the OP.

You're absolutely right, I forgot about the LS7 getting the dry sump back in 2006.

With this dry sump system I never understood why the wait 5-10 minutes requirement. On all the dry sump race motors I've worked on you'd dipstick it right after shutdown. Or the tank had clear tubing on the outside of the tank that allowed the oil level to be seen while the motor was running. The tank should be full at idle and right after shutdown. Shouldn't that level be what we measure?

So what gives Mr. Wizard?

^^^
I can't tell you the reasoning, but in the OM it states:

"Check the oil level between five and 10 minutes after the engine is shut down."

Da book says wait 5-10 minutes after shutdown of a fully warmed up engine and then measure. Ya wanna fight da book? I compromise and wait 7 minutes and measure.


Elmer

I didn't see year of your car or the total mile (though may have been embedded in a later post). NOW you know exactly why some of us absolutely refuse to have dealers "service" our vehicles... or, at the very, very least NOT without double-checking their "work" BEFORE leaving the premises. Sorry it's so, but it is... pure and simple.

Dude, you lucked out... this time. Forewarned is forearmed. :yesnod:

Your logic makes sense, but I can't explain why GM decided that we need to do it differently and requires that we do the hokey pokey prior to checking the oil level...

I don't have the explanation either, but obviously something about the design of the plumbing, tank, and sump, gives a too full reading immediately at shutdown. I have no doubts the engineers calculated the appropriate drain-down time to get the most accurate reading of recommended level, and that's what's published in the book

I also know that every time I change the oil, putting only 9 quarts in puts the oil level exactly between the two hash marks. That's good enough for me, and it's not worth worrying about any further.

[QUOTE=Red86Cfour;1599085348]With this dry sump system I never understood why the wait 5-10 minutes requirement. (Quote)

Here's an explanation I read quite a while ago. (Can't remember where, but likely on this forum.) The 10 minute requirement is because after shutdown, oil will gradually drain back through the scavenge pump into the sump and thus give an incorrect low reading on the dipstick. Waiting at least 5 minutes is because the return oil flows over several baffles designed to remove air bubbles produced by the scavenge pump. These baffles delay the tank from completely refilling, and thus a reading immediately after shutdown will also read low.

I couldn't agree more.

[QUOTE=Widgeon5;1599087968]Ok I think I get the idea but your explanation I don't think is quite right. or you have the terminology wrong. Totally agree that the longer you wait, the more oil in the tank leaks past the pump. But it doesn't leak through the scavenge pump. That pump stage (or multiple stages, some race motors have 3 or more) feed the tank (scavenges the engine) and so its tank inlet is generally above the level in the tank and will be uncovered after only a small amount of oil leaks past the pump gears. I believe oil is leaking past the pressure stage of the pump, this is very normal. This pump stage is connected to the bottom (outlet) of the tank and pressurizes the engine oil galleries. So basically whats happening is oil leaks past the pressure pump stage, and somehow that amount of leakage is limited. Once that amount of leakage is achieved (after 5-10 minutes per the manual) it is now time to use the dipstick to check the oil level.

I don't really think air in the oil is a big factor here. One of the reasons to have a dry sump system is to provide a better place to de-aerate the oil. Typical tanks have baffles, swirl pots, trap doors and other gizmos to help separate the air from the oil. So waiting until engine shutdown to allow oil to flow over baffles (like a sluice box) isn't really a factor here.

No puddle on the floor or smoke screen out the back then it must not have been filled properly #1 OR #2 did not wait to check dry sump .

I would have to concur with that. Good logic there! A breath of fresh air. I like logical reasoning on the forum once in a while. :thumbs:

GM should put a different oil cap on the dry sump engines with a warning to alert people. How many production cars come with a dry sump? How many owners bother to read their manuals? The combination of rare oil system, plus the vast majority not reading all the fine points is going to result in confusion.

Unlike a Z06 that screams "I'm different" a Z51 could easily fly under the radar as a base Stingray. The only clue is the dipstick and fill cap are in a different location, but a busy tech might not even notice.

I agree. Your dealer is feeding you a line of :bs on consuming a quart of oil every 1K miles. If it was truly doing that, you have a serious problem with the car. My guess is the dealer that did the oil change did not put all the oil in the car.

Obviously a way different motor, but 1983 chevy suburban big block 454. Burned a quart every 700 miles since brand new! But yeah, I'd expect juuuusssttt a bit better with the LT/LS motors.

Mine has a plastic tag attached to the oil cap with the instructions. But it can be pulled off.

Our 2017 Z51 has the tag. It has pictures telling to warm the oil to 175', shut down, wait 5-10 minutes, then check that oil is in the marked area on the dipstick.
When the original tag tore off somehow, I got a replacement under warranty. I also bought the oil cap that is marked "Mobil1 0W-40 Dexos", couldn't find one marked "ESP" or "Dexos2". What cap do the 2019's have?

My 2014 Z51 was used and has no tag. Never seen any pictures or mentions of a tag before.
So the dry sump cars have it (good) but they get lost or broken (bad). I bet many of them go missing after that first oil change.

:iagree:

[QUOTE=Red86Cfour;1599089841][QUOTE=Widgeon5;1599087968]

Ok I think I get the idea but your explanation I don't think is quite right. or you have the terminology wrong. Totally agree that the longer you wait, the more oil in the tank leaks past the pump. But it doesn't leak through the scavenge pump. That pump stage (or multiple stages, some race motors have 3 or more) feed the tank (scavenges the engine) and so its tank inlet is generally above the level in the tank and will be uncovered after only a small amount of oil leaks past the pump gears. I believe oil is leaking past the pressure stage of the pump, this is very normal. This pump stage is connected to the bottom (outlet) of the tank and pressurizes the engine oil galleries. So basically whats happening is oil leaks past the pressure pump stage[QUOTE]

As I think about it, I believe you are correct. The drain-down would be occurring through the pressure pump.

Because the scavenge pump's flow capacity must be higher than any possible flow from the main pressure pump (to keep the sump "dry") it will necessarily be pumping some air along with the oil. This aerated oil flows over the tank baffles all the time the engine is running, and for some period of time after shutdown. I believe this is the reason for waiting at least 5 minutes to check level.

[QUOTE=Widgeon5;1599092868][QUOTE=Red86Cfour;1599089841]No doubt there is air whipped up in the oil that is dissipating during the wait period, but I think its more to do with the drain back through the scavenge pump as the tank is way too small to hold all nine plus quarts of oil (when you do an oil change for example). Also, after the motor is shutdown there naturally is no more flow since the pump isn't pumping. The only deaeration of the oil is the air bubbles traveling to the surface and popping.