i have a Mercedes type 124(250 D) diesel,and it runs very good,but it produces a lil bit of black smoke than usual,otherwise it does not spend oil,engine runs very good,what do u suggest???

What year is this vehicle?

it is 1986

The only thing I can suggest is keeping up the tune up on it.....how many miles on it, I know these vehicles can carry alot, the smoking is probaly valve seals and a conpression check would let you know what shape the engine might be in and the last thing you want to hear is someone telling you need a ring job... what shape are the glow plugs in?

it has 120000 miles originally,compression is great it doesn't heat up up even if there is a terrible traffic jam,mostly the temperature is 80/celsius,the oil pressure is between 2/3,

Thats good,...then I would focus on valves stem seals, the thing is that after 10 to 15 years any rubber seal composition starts to break down .....faster when its dried out. BTW what were the compression readings on the cylinders?

I don’t have much to do with diesels but doesn’t black smoke mean it’s over fueling?

Dan.

Canadian "EH"

Black smoke usually is a sign of an over rich fuel system on gas models,but when it comes to these deisels with some age on them its hard to tell, if its the fuel seems like it would be hard to start plus that smell would be strong enough to get your attention, the glow plugs also be a factor,....being in the south people here worship these vehicles...like the 7.3, they quit making them , the newer ones will drive a person crazy trying to repair....I myself prefer good old gasoline

 I dont know about the compression readings on the cylinders,but it reaches 110 miles per houer very easily,I will definetly focus on valves steam seals,