I've been reading alot of "smoking" diesel threads in hopes to figure out what's going on with my 92 300D 2.5 turbo diesel. I recently purchased the car as a mechanic special and towed it home. It always starts immediately but the idle lopes right away. It smokes whitish grey and sometimes a little black mixed in and seems to load up if I let it idle too long. I DON'T smell any sweet antifreeze burning and there is no excessive pressure coming from the reservoir cap. It has a hesitation on lower rpms but seems to run pretty well from the mid to upper rpm range. After you rev it up, the smoke diminishes a little but quickly worsens again when returned to idle (loads up). It knocks a little louder as it loads up.

I showed it to my buddy who owns 3 turbo diesel 300 Merc's and he was convinced that it was my injector nozzles. I replaced and balanced all 5 nozzles only to get the same results.

I decided to start my own thread so that I'm not confusing w123 or w126 solutions with my w124. There's a bit of oil in the turbo and the crossover tube and some thick sludging inside the intake side (if that's what you call it) where the turbo crossover piece connects. I have yet to do a compression test, although that's probably what you all will suggest first.

Being my first Mercedes, I don't want to just start replacing parts randomly and would like to follow a logical routine knowing what to check first, second and so on. I think that my nozzles may have been fine now that the car's symptoms are unchanged. I am experienced with gas engines, but diesels are new to me.

I'm amazed at how good it sounds when you hold the gas pedal just above the hesitation point...it even smokes slightly less.

Should I begin with a compression test at the glow plugs? If it's low on one or more cylinders should I pull the head off next? Could it be timing (like I have read about on the older models). If I start the car without the turbo crossover connected (to see if smoke goes away) will I hurt the engine or the turbo?

Thanks in advance for your help...this place is great!