i have a 05 sxt. It just started doing this after my recent oil change last week. After the car sits for a few hours or so or over night it will smoke for about 5 seconds....and its a blue smoke and to me it smells maybe like oil burning off. Could it potentially be time for a top end rebuild. it has 140000 miles. I was thinking maybe cracked valve or something. Can someone please help me.

 

Did you use an oil brand/weight/type that you don't normally use?

 

Smoking only on startup is the sign of bad valve seals.

If your mechanically inclined they can be replaced without head removal or cam removal with proper tools and compressed air in cyclinder.

The procedure requires you remove all rocker arms, all plugs, inserting a compression tester and then removing the gauge for compression test and using compressed air ( not oxygen!!!!!!! ) to pressurize the cylinder.

Once pressurized you can remove one valve spring at a time with a topside valve spring compressor and not worry about the valve dropping into cylinder while you replace the valve seal. Obviously you must only do this to the cylinder which is pressurized so 4 valves if SOHC, then move onto next cylinder pressurizing that before proceeding.

This is more along the lines of an advanced job and should only be done by those qualified to do so. If something goes wrong the valve will drop into cylinder and you will be forced to remove the head.

This is a time consuming job as well.

The other alternative is to pull the head and send it to a machine shop and they can replace them for a small fee.