This Service Information bulletin and attachment supersedes SI B11 08 15 dated November 2015. SUBJECT N63 and S63 Engine: Valve Seal Replacement. Refer to the following applicable SIBs before replacing the valve seals. B11 07 11 - Turbocharger Failure: Oil Supply and Return Line Blockage and Proper Repairs B11 07 12 - N63 Engine: Oil Consumption and/or Rough Running Complaints B11 01 13 - N63 Engine: Engine Oil Consumption, Engine Oil Top-ups and Refill Capacity B11 03 13 - Engine Oil Consumption (all models) If the valve seals are leaking, one of the following will help determine if the seals should be replaced. Smoke from the tailpipe when starting or aggressively accelerating and decelerating the engine Excessive engine oil consumption Spark plugs fouled with engine oil