My 2000 Maxima blows smoke when I start it up! The longer the engine runs the more smoke it will blow when restarted. For example, if I just drive around the block and back, nothing! However if I drive say 10 miles or so, it will blow at restart. This condition will completely exaust the oil supply! Nissan says possibly an injector leak or valve seal leak.

Hi,
I am not a mechanic, but when the car gets hot, and starts blowing smoke, it means that something has expanded when it's hot.
Blowing smoke isn't a good sign, as I'm sure you know. You might take it to a reputable garage, not the Dealer, but a garage that doesn't charge as much as a Dealer to look at it, and give you an estimate.
Best of luck.

Could be three or so things, the smoke could just be water in the muffler and exhaust pipes ( you'll see dozen others smoking from which) or it could be just the weather, ( hot damp air and cold air makes steam) or a coolant leak, that will cause water to run down the exhaust, or it could be oil, since its cold, metal shrinks, though of course sometimes the metals can expand differently, oil could be getting by the rings, or the rings have gotten stuck ( rings as in piston rings, they can get crudded up between, which they should be free, cause oil consumption, etc.) or a valve stem seal/seals. Have you noticed the oil level dropping? Then that would stand behind it being oil... and don't use any kind of oil stop leak...

Is the smoke black? Or Is the smoke blueish in color?
Is the check engine light on?
When the smoking occurs, is there a noticeable loss in performance and or the way the transmission shifts? (if its an automatic)
Have you serviced the O2 sensor?
Which motor is in your Nissan?
Have you checked with the dealer for any Technical Service Bulletins that have been issued for that yr make and model?
I need to know the answers to these questions before I can give an educated guess.
Thanks

What is the mileage on your car ? Maxima's are excellent cars and I have owned two. Two things come to mind. 1.) A vehicle will smoke if the air/fuel mixture is out of whack. This would not burn any oil. So, I would think that your valve stem seals need replacing. I do not think a car that age would have worn or damaged piston rings unless it has been misused.

Peace.