According to the 1999 Lincoln Navigator Owner Guide ( 5W-30 )
According to the 1998 Lincoln Navigator Owner Guide : ( 5W-30 , 6.0 U.S. quarts with engine oil filter change )
According to the 2001 Lincoln Navigator Owner Guide : With engine oil filter change : ( 5.7 litres / 6.0 U.S. quarts of 5W-30 engine oil )
my 98 navigator service guide said 8000km. hope that helps
According to the 1999 Lincoln Navigator Owner Guide : For the 5.4 liter V8 engine ( 2 valve and 4 valve ) With engine oil filter change : ( 6.0 U.S. quarts of 5W-30 engine oil )
According to the 2002 Lincoln Navigator Owner Guide : ( 5W-20 engine oil is recommended )
According to the 2006 Lincoln Navigator Owner Guide ( 5W-20 )
According to the 2008 Lincoln Navigator Owner Guide : With engine oil filter change : ( 7.0 quarts of engine oil )
According to the 2006 Lincoln Navigator owners manual ( 5W-20 )
With engine oil filter change ( 7.0 quarts ) according to the 2011 Lincoln Navigator Owner Guide
According to the 2004 Lincoln Navigator Owner Guide : With engine oil filter change ( 7.0 quarts )
According to the 2000 Lincoln Navigator Owner Guide ( 5W-30 ) * with engine oil filter change , 5.7 litres / 6.0 U.S. quarts of 5W-30 engine oil
The PCV valve located is on top of the valve cover. It is right beside of the oil filler cap.