1999 E300 Turbo Diesel
 

My 1999 E-300 TD (62,000 Miles) has an unusual problem. It's using engine alot of engine oil. The car starts perfectly, and there is absolutely no smoke. (not even a slight amount when starting.) Once the engine is warmed up, and it idles for 5 minutes, an enormous amount of blue smoke comes from the tail pipe. At this point it appears to idle a bit rough. Get in and drive it and it goes away. The performance is perfect with no loss in power, but the fuel economy has eroded to less than 30 mpg. The car doesn't use much oil during long trips, but needs a quart of oil every 500-600 miles. Those miles include city driving also.
With the car in park idling, I've accelerated the engine up to 3500 to 4000 RPMs and when I reach those speeds, the engine remains smooth up to those speeds, but then starts missing and an enormous amount of smoke emits from the tail pipe. Do this two or three times and then the engine will stop smoking an can go up to 5000 rpms and back down with no symptoms like just previous.
I think I've got an diesel pump timing issue.
The turbo has been inspected and and there is no oil leaking in the exhaust system or in the intake (compressed) side for the intake.
What can the problem be? Valve guides should smoke when starting, or all the time.
I've had the engine cylinders compression tested and they are well inside the recommended range.
Joe

What is the oil change history? Even with the timing off the car should not burn oil? I would start by pulling the injectors and getting them checked out. That is simple and cheap. Then I would find out how to time these things and do it myself or probably have the dealer do it.

Did this happen all at once or over a period of time?