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Discussion Starter #1
I have 2016 NOx . On cold start it sounds rough and idles high for 15 to 30 secs then comes down. There is white smoke from tailpipe at start up and while driving. While driving it will come and go. Not overly thick but thicker than usual. Also seems like milage has dropped. Purchased 1 month ago from dealership. Feeling vibration in the vehicle as well.
 

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What do you have? A 4 or 6 cylinder? How high was the RPM when you start it up? My 2.4 starts up at 13k RPM and once in motion it goes down to 900-1000 until it is fully warmed up. If it is cold outside the white smoke could be vaporized exhaust gas. When you feel the vibration? In motion or standing still?
 

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Is the level in your coolant tank dropping?
Keep a close eye on your antifreeze.
 

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Superdave - if your running at 13k rpm, now I know where you got your name from. Lol
 
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Probably just the cold air. All cars do it hot engine exhausts meeting cold winter air, come and goes longer you drive it. Some cars are just more pronounced in it than others especially a 4cyl. Moreso if it's humid outside.

You would know if it was blown head gasket be a smoke screen where you couldn't see through it non stop.

Mine idles high for like 15 seconds when I start up then lowers to like 750-800. Can usually hear the difference when I remote start.

Drop in gas mileage probably again due to winter fuel and if you preheat the car etc. My mpg sucks because I like to prestart. Still even without prestarting I don't get what is advertised.

Shaking I'm unsure about my old 13 nox before it got totalled liked to vibrate a lot. But my new 13 doesn't. Wondering if related to transmission or motor mounts etc.
 

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Discussion Starter #8
Thanks for responce. It's 4 cylinder. The tailpipe and housing smell sweet. I didn't mark but coolant dropped maybe quarter to half inch
 

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Yea that's a blown head gasket for sure these things have a metal head gasket without oil running through the cylinder walls although not too common... if someone ran it dry even for a little bit the gasket is blown between the combustion chamber and water jackets....
17303


pretty hard to replace on your own even it will cost at least 400 bucks and a week and even to attempt that its a lot of extra work in my opinion i wouldn't even attempt it without pulling the timing cover and just pull the whole timing chain off. Since it is metal though you may not see ton of hot action going on until you get it really warm.... I would take it back to the dealer....

where I added the red is where the head gasket is probably leaking and u wont see a milkshake "really" in the oil like a old car a good spot to check is flip the oil filler cap upside down u will see it there.
 

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Test for exhaust gasses in the coolant resivwar ... rezivwar? idk but yea thats the only way to be positive there is strips or a smog test facility can hook up a sniffer pretty cheap. There is a class in the baja 500 that mainly use this motor... its built like a train engine or something its very simple and runs good even with major problems like u could literally drain half the oil and coolant replace the rest with sand and probably not tell the difference. If you are having any vibration thats abnormal, gm motors of this era are smoother than any other car ive ever driven. Umm superdave has titanium valves and forged steel internals, tuned running on nitromethane... he has the fastest nox on the forum idk if I would go that extreme.....😝 lol
 

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Discussion Starter #13
You guys are like gurus. I have an extended third party warrenty .I almost cancelled my extended warrenty yesterday. What part would be the culprit? Going out on a limb but I doubt gm LMT GM powertrain covers it. I still have three months. Can't thank you guys enough
 

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Discussion Starter #14
Ya the only l filter is where I took my swab from. A couple hours later my friend comes by to have a look. The oil colour looked good then and no smoke. Must be slow right now anyway. The dealer might have to take it back. U gotta NB post pick of your vehicle's
 

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Test for exhaust gasses in the coolant resivwar ... rezivwar? idk but yea thats the only way to be positive there is strips or a smog test facility can hook up a sniffer pretty cheap. There is a class in the baja 500 that mainly use this motor... its built like a train engine or something its very simple and runs good even with major problems like u could literally drain half the oil and coolant replace the rest with sand and probably not tell the difference. If you are having any vibration thats abnormal, gm motors of this era are smoother than any other car ive ever driven. Umm superdave has titanium valves and forged steel internals, tuned running on nitromethane... he has the fastest nox on the forum idk if I would go that extreme.....😝 lol
💪 LMAO 😂
 

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Sounds like your in a hard spot, just a warning don't go smelling the sweet exhaust too much when you have a blown head gasket. It is toxic and could potentially hurt someone like even a tsp of radiator fluid could.. also driving like that could be putting excess pressure into the cooling system. Sometimes...when head gaskets are going bad you can look at the crack between the block and the cylinder head you can see them seeping too.
 
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