bchallus
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- Nov 16, 2025
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- Buick Ownership
- 2009 Buick Lucerne Super
I'm trying to pinpoint a problem i'm having with my 2009 Buick Lucerne Super 4.6l Northstar V8. Recently it starts up rough and has cylinder 3 misfire code. Also throws a Service Stabilitrak message on and off, along with a check engine light, and white smoke out of the exhaust. I heard a faulty PCV valve can mimic signs of a blown head gasket. I changed the oil, no milkshake consistency or anything along those lines. Oil was about 2qts low even though it had "10%" oil life left. There has been no other signs of a blown head gasket minus the fact I can't seem to get the coolant levels correct after changing a thermostat a few months back. It clearly had air bubbles in the system because heat would blow cold until I revved it then it would come back hot. All of this being said I'm praying it's not a head gasket as the car only has 79k on it.
The check engine light and the service stablitrak message come on and off randomly, and after a few minutes of idling super rough it calms down and drives like normal. Also when I go to turn the car on for the first time, it starts to crank and cuts completely about 1 second in.. then turning the key off and back on it starts right up still idling super rough. The white smoke comes and goes randomly as I drive it, but always blows white smoke when it's idling rough.
My main questions are... Where the hell is the actual PCV valve, and can it really replicate signs of blown head gasket with signs of white smoke out of the tailpipe, and cylinder 3 misfires like I read online? I hear that the PCV system is inside of the intake manifold and there isn't just a valve you can replace. I'm lost with this car because there is hardly anything left that I can figure out to help me learn if my car is a tin can, or if it's still worth about 7k. PLEASE someone help me with some intricate opinions on what is really going on, PCV locations and systems (if it even has a valve), and what to do now.
Thank you to whoever read my whole post.
The check engine light and the service stablitrak message come on and off randomly, and after a few minutes of idling super rough it calms down and drives like normal. Also when I go to turn the car on for the first time, it starts to crank and cuts completely about 1 second in.. then turning the key off and back on it starts right up still idling super rough. The white smoke comes and goes randomly as I drive it, but always blows white smoke when it's idling rough.
My main questions are... Where the hell is the actual PCV valve, and can it really replicate signs of blown head gasket with signs of white smoke out of the tailpipe, and cylinder 3 misfires like I read online? I hear that the PCV system is inside of the intake manifold and there isn't just a valve you can replace. I'm lost with this car because there is hardly anything left that I can figure out to help me learn if my car is a tin can, or if it's still worth about 7k. PLEASE someone help me with some intricate opinions on what is really going on, PCV locations and systems (if it even has a valve), and what to do now.
Thank you to whoever read my whole post.
