If you mean oil and fuel filter change, plus check all the pencil anodes, belts and hoses, then this is a DIY job plus the cost of the parts. Mine on my Cat engines cost about £150 for the oil plus filters for the 2 engines. If you employ a technician, then this will be 2 or 3 hours work so budget another £150. Clearly if anything else needs replacing then the costs rocket north rapidly.