I vote for a sticky lifter.  Have had the problem with both the '86 
     Golf and the '91 Westfalia (just can't bring myself to use that 
     "other" too-cutsey nickname).  Ran a can of Alemite CD-2 in the Golf 
     the day before an oil change - no more noise.  Just treated the 
     Vanagon this morning.  Oil comes out tonite.
     
     -Blaine