[ainarssems]

2 years is a long time for oil in the engine especially for diesel with DPF. With 11k miles over 2 years I guess you have been doing a lot of short trips which are known to cause excessive DPF regeneration cycles. In the DPF regeneration cycle fuel is injected late in working cycle and /or exhaust cycle to get more heat in DPF and burn off soot. Because it is late in the cycle not all diesel burns , some ends on cylinder walls and gets washed down in sump causing oil contamination. In extreme cases you can even see oil level rise and oil contamination with unburnt diesel can reach over 50% in 10k miles.