I have a 98 430(sport), 33K miles, use synthetic oil. When the car has been sitting a day or more it gives off a puff of blue smoke when started. No noticable oil consumtion.Should I worry or return to dealer as next year I have to decide to buy or return at end of lease? PS love the car!! Thanks.

That is a classic symptom of leaky valve guide seals. In my opinion, it is not critical. I would wait until you had some other need to crack those valve covers.

What happens is when you park your car for an extended period of time, the oil trapped on the top of the head leaks down past the valve guide seals and into the combustion chamber. There isn't a lot of oil sitting on top of the head, so you won't get any more oil than what you see burning already no matter how long it sits.

Since the car is still under warrenty I would have the dealer check it out especially if you intend to keep the car. A new car like your's should not have any smoke at all no matter how long it sits. I would bet one or more valve guides are lose. Make sure they spend the time to check it.

follow up question
 

Is there any serious nature to this problem? How involved is the repair? I would like to wait until next year or next repair. Thanks

If the valve guides are loose you are looking at the head job. Roughly $3500 to do all eight cylinders. If it is the valve seals, it is about $600. There is no harm in waiting until the next service to have it repair. I would definitely get it done before the warrenty expires.

A car of this vintage with the stated miles should not be producing blue smoke. If valve seals are the problem, then take it back to the dealer and get a solid diagnosis. This should be covered by warranty. If the return holes are partially obstructed (for whatever reason), this is also an issue for the dealer. The way I see it, they own the fix on this one..

The car is under warranty. It doesn't matter if the problem is valve seals, a loose kabobulator, or it needs an entirely new engine, don't hesitate to take it to them and have them fix it. You pay a premium price for a new car, and they owe this to you. I'm not one for getting something from them that they don't owe you, but warranty work to keep the car in proper condition is something that you paid good ( and I expect hard earned ) money for.

Good luck,

Thanks
 

Thank you all. I made an app. for mid January.I ll let you know the outcome. Mark