Couple of thoughts (some perhaps angry) from my experience with the LC9 in my 2011.

Blowing a lot of smoke at startup is oil sitting in the cylinder(s). Fouled/stuck rings. I know the bad valve cover in mine was starting to burn enough oil to carbon up and cause the control rings to stick, which leads to more consumption. I drove it like I stole it (pedal to the floor a couple times a week on the highway) and the little puff of smoke I used to get at startup in the morning went away. I noticed it starting to consume a bit less oil and then I found out about the valve cover problem. I just got an oil change two weeks ago. About 3500 miles on it since the cover replacement. If it burned any, I couldn't tell from the level on the stick. Didn't go down at all that I noticed. I still floor it a couple times a week to and from work just because it's a habit now. Never hurts to give the control rings a workout.

How much oil is yours using? Badly stuck rings is going to use quite a bit. Worn rings is also a possibility from lack of lubrication. I've heard of a quart every 500-1k miles, which even GM considers excessive with their loose standards. If you see it using this much, get it into a competent dealer ASAP and have them start a consumption test. They won't do or recommend (since you're out of warranty) anything until a consumption test is performed. And keep an eye on your oil level yourself. If it's smoking like you say, check it every day or at least every other day. And if you take it to a dealer, do not let their service dept, a tech nor a service manager give you any bull****. If they overfill, call them out on it. Always check your level right before and after they touch it and make your own notes. Some bull**** I had to call out was that they topped it off every time when I was doing my consumption tests, which is fine, but they NEVER put that on the repair order. They said, "well, that's standard procedure so we don't have to document it." I said, **** you!, it's warranty work and you document everything or I'm calling GM first and the state's attorney right after. So the paper trail would show that it was 1/2qt low at each 1k mile check. And not 1/2qt low, TOPPED OFF. Then another 1/2qt low and TOPPED OFF again. By the time I was done with the first test, it was somewhere at or just under 2 quarts low over that 3k miles, which is GM's "normal" consumption rate. That's when I found the TSB for the valve cover and took it to the original dealer. I said, I'm not going through the consumption test bull**** again, just replace the cover or give me my money back.

Do you know if it has had the left valve cover replaced yet? If not, it would be a good idea, because it does contribute to consumption. It's a $100 part and about 30 minutes if you can do it yourself. Although I'd say the valve cover being the main culprit is unlikely if it just started smoking and using oil like crazy. The old cover was just a **** poor design and resulted in oil being sucked into the intake via PCV under the right conditions (light throttle like lots of city driving). In my case, that led to all the carbon fouling.

Check the build date on your door tag too. There's also the problem with the AFM pressure relief valve in the pan spraying oil up into the cylinders from the bottom. They resolved that by adding the deflector/shield to that valve. I believe they started adding the shield for Oct. 2010. Mine had it from the factory (11/10 build). But again, if this just started out of nowhere, this is also unlikely.

 

Not sure on how much oil it is using yet, Just started testing it this week. My build date is the same as yours 11/10 so I assume it has the deflector on the AFM Valve as well. The valve cover you replaced was Left (Driver Side) ? or Right (passenger side)?
I am having the AFM turned off on mine also, heard it can add to this issue. Already have a tune so cost me nothing to have it turned off and then I dont have to hear it sound like a mad bee in 4 mode.

 

Yes, the left aka driver's side valve cover has the PCV orifice integrated.

 

Ok thanks, Do you happen to remember what the updated valve cover part number is? I have found Dorman cover for pretty cheap online. Even orileys has them for 75 just not sure if it is the new one or a replacement of the old style.

 

Never mind I found it. GM revised version is 12642655
Dorman Same Version 264-969

Thanks again for the help

 

Yep, that's the p/n. Check eBay. Saw a couple on there yesterday for <$80 new, genuine GM.

And if you're going to do this yourself, google for the PDF of TSB 10-06-01-008M. You'll probably only find 008G though. Close enough. It shows what to look for in the old cover. Hardened deposits in the baffle drain hole is probably the most obvious. Mine was starting to seep all around the gasket onto the head. They didn't show me the old cover, but I know it was bad.

My oil filler cap also had red goop all inside it. Which concerned me that maybe some coolant was getting into the oil. No, it was just rusty sludge steaming up. Wiped it off, hasn't come back.

Do yourself a favor and replace all of the spark plugs too. I don't think they did mine. Probably end up doing them myself at 90 or 100k. Mine is still idling a bit rough, but no misfires, or at least not enough to turn on the idiot light. Valvetrain is still noisy. Oh well. Still not completely convinced that I don't have bad cam bearings. Screw it, not gonna rip it apart. Just wanted the oil burning to stop so all of this doesn't get worse.