My 98 E300DT now smokes at start-up, hot or cold or even somewhere in the middle, after it has sat for an hour or more. What is the typical cause of that?

Please keep in mind that I just had all 6 glow plugs replaced, the long glow plug with after glow where I understand that they have to take the head off in order to get the job done.

Thanks, Jay
mailto: jpquinn@home.com

They have to take the intake off, but not the head. The job should pay 2-3 hours or so to do properly including diagnosis of the failed plugs.

You could have a leaky injector or a timing issue/ I have also seen quite a few fuel leaks from the plastic lines. This will allow air in and can cause weird behavior.