I checked the oil in my Transit Connect TDCi today and it's as black as the ace of spades.
I changed the oil and filter earlier this year, 4000 miles ago. Should I change it again or does it not matter that it's black as coal? I know oil in diesels does go black but I've done 5,000 in the Defender TD5 since the oil was changed and it's not gone as black as this.



