Start up
 

1993 300D 2.5T. As soon as the GP light cycles, the car will start right up, idle smooth for 5- 10 sec. then idle rough with white/blue smoke. When temp reaches bet. 40 - 60 C no smoke and runs great.
Uses no oil, new fuel and air filter, has lost abt. 1/2" coolant in res. tank in past month. Could this be a leaky inj. or????

Maybe a compression problem? The glow plugs stay on for a few seconds after the engine starts then compression and engine heat play a bigger role. If compression isn't right, it takes longer for sufficient engine heat to smooth the idle.

Could also be a lot of other things.

Coolant loss is worrisome. Better have it checked.

Sixto
95 S420
87 300SDL

Worth having a look at your oil filler cap for emulsion on the inside look at dipstick for water in the oil, white smoke on a diesel,would make me think head gasket particularly with coolent loss good luck