I have a feeling a good syn oil would go 6-8k in your 617.

My 606.962 usually goes the FSS max of 16K and M1 T & TD 5W/40 still has +50% of it additive pak left. Insolubles are less than .5%. Yours will test out higher on both at less mileage due to its engine design.

__________________
Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)