Mitsubishi Repair: mitsubishi exhaust fumes black, glow plugs, fuel flow

Question
hi i have 2.8 diesel mitsubishi the head and gasket were changed last july but 6 weeks ago there was pressure and the head was taken off and another one put on [ new ] there are now black exhaust fumes when the car changes gear , it is automatic , the car has been standing for about 6 weeks  the car is not overheating and no pressure building up  water level is ok

Answer
Janet,
This is not an engine used in any vehicles in the US, so I don't have specific information about your situation.  But in general, excessive black smoke usually means an the air to fuel ratio mixture is off, and that your engine is getting too much fuel.  You can have your mechanic check the fuel flow and make sure nothing is blocking the air intake flow.  Have your glow plugs checked and replaced if necessary.
Good luck!