Most of the times, this condition, known as "Oil Sludging", is caused by crankcase ventilation problems. The best way to see the severity is to remove the left side (driver's) valve cover and check for accumulation there. Make sure you have a new gasket on hand before you start #112 016 02 21. Read all the information supplied, and pay particular attention to clogged and or missing vent holes. Also check for soft or clogged breather hoses attached to the valve covers.
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