Why has the oil in my diesel car turned jet black?
I have a Subaru Outback 2.0d Premium which I have owned from new. It has done 11000 miles (mostly high speed long distance and motorway) and I have noticed that the oil level is creeping up. The car was serviced (oil change as well) at 8700 miles and the oil is already black as pitch. Subaru dealer says I need to thrash it more but my right foot is fairly heavy and I suspect my clean licence has more to do with good luck. Any ideas?
The DPF is not actively regenerating and instead the extra diesel injected into the engine to promote regeneration is sinking into the sump. It urgently needs to be drained out and replaced to the correct level. Diesels can blacken their oil very quickly, but there is something wrong with yours. If the supplying dealer won't fix it, write a letter to the dealer principal expressing your misgivings and demanding he take the car back and fix it. Send this by post office special delivery, keep a copy and staple the certificate of posting to the copy. If this isn't fixed quickly the compression ignition engine could start running unstoppably on the oil in its sump and could blow itself up.
Answered by Honest John on