1 Diesel Knock "they will tell you its normal" it is NOT - back in the day we knew it as (Pre-Ignition / over fueling or possible 2 ( "over advanced spill timing") - worn injector pintle nozzle that is "not atomising" the fuel resulting excessive black smoke - modern day ECU control cannot stop this entirely, check your engine oil colouration / carbon content from the last service - if it is black as or possibly fuel diluted = over fueling -----test for dilution, drip eng oil onto very hot plate it should just smoke not fire/flame up. I have to say cant beat the old diesels before ec
