Thanks Rumcajs. Will take on board re egr. Problems caused as you stated. Have dyno'd it before and after, run it on the highway, uphill and down dale, self tested at the recommended 26/27 hundred revs. etc etc. Only thing that worked was removing the egr blockage plate. I am not a mechanic and have little knowledge re the workings of the zd 30 engine and its electronics. I'm having the catch can fitted hoping that it will eliminate the "gunk"build up. Will also convey your experiences with the fan to the motor rebuilber. Thanks. Gypsygiant