I wud suggest every 5000km. IMO safe ka dito. Everyday car ko is a Civic HB. 195,000km na ok pa engine. I changed timing belt 2x na and 1x ng water pump. Wala na aside from that. Sa mga diesel engine mas mahalaga regular ang oil change. Kung di mo masyadong ginagamit di change oil ka na lang and keep the filter. This is my experience. :lol: