If the oil has been changed regularly, engine will go the distance. Remember that 606 head is aluminum, so some blow head gasket at cylinder #1- oil & coolant dump into cylinder (not oil into coolant), so obvious heavy blue and white smoke. Engine has hydraulic lifters, so valves don't need adjusting, but they can fail depending on oil changes.

A good sign if the coolant is correct gold color MB or Zerex G-05, and not the green junk.