Jesus am I glad I asked here first now I've searched again it seems best way is crank cas and fuel tank or fuel filter after a service! Basically I have a 04 mondeo tdci and it hasnt been serviced for 5 YEARS!!! It runs ok but has no low end power (under 2k rpm) until the turbo kicks in the a big cloud of black smoke kicks out! I've cleaned the egr valve ( just with a rag first time I've done any form of "mechanics" lol) been told it may be bungee up injectors and seafoam is suppose to be the Mach daddy of injector cleaners! Gonna do it tomorrow so fingers crossed >_<