Engines manufactured 4 May 2011 and earlier: Oil consumption, poor idle quality, smoke from the exhaust, oil smell, or low oil level may be caused by:
External leakage of oil, especially around the cylinder head, valve cover, and timing cover area
Over-filling of oil
A valve cover that was improperly sealed from the factory, which can be determined by a successfully-passed cylinder leakdown test combined with excessive soot on the cylinder #6 spark plug. Volvo remedied this in production on 15 April 2010.
Valve guide leakage, which can be determined by a successfully-passed cylinder leakdown test combined with excessive soot on any spark plug except cylinder #6. The most common symptom of this is white smoke from the exhaust.
