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Kind of hard to tell whether its smoke or vapor. Does kind of look like smoke, but:
  • You say the oil level seems high. Are we dealing with dry sump (Z51) or normal engine? I'm assuming non-Z51, but please verify.
  • If a dry sump, are you familiar with the procedure for checking the oil level?
  • How many miles on the engine?
  • How did you warm the engine and for how long? And how long was it not running until you started it for the video? At 55*, depending on the location, its possible for a warmed engine to blow vapor on a restart as the exhaust is probably the first thing to cool off and vapor forms as the exhaust re-heats.
  • Does it smell like smoke? or just exhaust?

I would do a cold (first of the day) start and see how how it does. Leaky valve seals will smoke on a first start and a re-start after setting a bit. Then take it for a ride, leave it running, set up the camera, and give it few raps and see if it smokes then. And maybe not so close to see more of the smoke/vapor and the color. If it is really smoke the next step would be a compression test to determine valve seals or rings.
 

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Welcome to our forum and congrats on your C7. As noted by troutwilly, do you have a Z51 or non-Z51? The way to accurately measure the oil level is very different depending on which one you own. His other suggestions are also worth noting.
 

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Discussion Starter · #4 ·
This is a 2016 Stingray non-Z51 with 14K miles on it. I had it checked out by a Corvette specialty service shop before I bought it and they said everything was good but they didn't perform any leak down test or compression tests. I'm going to record the cold start today (it's really cold outside too so i'm going to have to wait). I'm also going to check the oil before start. Everything should be settled into the oil pan by now so the reading should be correct.
 

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What color is the smoke?
Black? Likely fuel.
White? Likely steam/condensation/engine coolent
Blue/gray? Likely oil
 

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The smoke looks darker than anything that i experience. Plus the tips are really filthy which could indicate an issue. (not that everyones are shiny but looks like these have never been cleaned)
 

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My tips look just as bad as yours and i don't feel I have an issue. I watched your vid and noted what appears to be gray/blackish smoke during and right after a high rev. This indicates to me that its unburnt fuel, hence your black tips. I dont find this a real issue on my car. Note: it takes a sec for your varible timing to catch up enough to detonate all the fuel being dumped into the cylinder.

Try this, rev your engine and hold it there (4k rpms). If you get continuous black smoke pouring out, then I would suspect you have an issue. My car doesnt smoke at high rpms, only after high revs. Im happy with mine.
 
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This is a new to me C7. Car was up to operating temp and it was a cool evening about 55 degrees. I checked the oil level after the video and it is clean but it seems high to me.

Smell is a good indicator as well. If it smells burnt kinda tar or fresh asphalt that is usually oil. If it smells sweet that is usually coolant. Water vapor generally smells like nothing or steam.

You can also pull a spark plug and look for fouling.

I have the same problem with my oil is super clean and hard to see. The only way to really fix the oil level is to change the oil and put in the correct amount. If the smell goes away after a bit when you change the oil then it was overfilled.
 

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Kind of hard to tell whether its smoke or vapor. Does kind of look like smoke, but:
  • You say the oil level seems high. Are we dealing with dry sump (Z51) or normal engine? I'm assuming non-Z51, but please verify.
  • If a dry sump, are you familiar with the procedure for checking the oil level?
  • How many miles on the engine?
  • How did you warm the engine and for how long? And how long was it not running until you started it for the video? At 55*, depending on the location, its possible for a warmed engine to blow vapor on a restart as the exhaust is probably the first thing to cool off and vapor forms as the exhaust re-heats.
  • Does it smell like smoke? or just exhaust?

I would do a cold (first of the day) start and see how how it does. Leaky valve seals will smoke on a first start and a re-start after setting a bit. Then take it for a ride, leave it running, set up the camera, and give it few raps and see if it smokes then. And maybe not so close to see more of the smoke/vapor and the color. If it is really smoke the next step would be a compression test to determine valve seals or rings.
Leak Down Test may help diagnose. Also, "smoke" from water vapor feels like water when you rub it between your fingers, like oil if it is not water.
 

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The LS series and new LT series engines in our Corvettes are incredible on so many levels. If properly maintained, they will last many decades of spirited use. However, abuse is a different story. It doesn't take much talent to over rev a motor, miss a gear shift, or do some serious damage to any engine. Fortunately we have rev limiters built into the engine management system, but that will not prevent someone from breaking a piston ring that would or could cause excessive blow by. A cylinder leakdown test and a compression test may find the damaged cylinder. We have all witnessed irresponsible Corvette owners showing off when leaving a car show or some other Corvette gathering. They will wind up their motor until the rev limiter kicks in and attempt to powershift their cars. They literally have no idea what they are doing to their Corvettes and the worst part is, in many cases they don't care. We all know these type of guys and we have said to ourselves, "I would never buy that car" because we know how it has been abused. Unfortunately the selling dealer doesn't know what that particular Corvette has been through, and you are the unfortunate second owner. If not cracked or broken piston rings, then it could be bad valve guides. Insist on having your potential purchase looked over extensively by a independent tech that you know and trust before signing any agreements.
 

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Welcome to our forum and congrats on your C7. As noted by troutwilly, do you have a Z51 or non-Z51? The way to accurately measure the oil level is very different depending on which one you own. His other suggestions are also worth noting.
Not only is the WAY you check it very different, so is the LOCATION where you check it!
 
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