My humble 2 cents worth...
If the vanagon engine wasn't supposed to be run over 4000 rpm, wouldn't the
redline be at 4000 rpm?  Shouldn't the rpm limiter kick in at 4000, not 5300?

The Tiico engine redlines at 6400 or so, and 4000 is much less than that.  My
old WBX ran for 250000 miles with no leaks or problems, no head problems, and
using green antifreeze (gasp!) taking full advantage of the higher speed
limits.

Good lord, its a car -- drive it!  If it gets hot, slow down.  Check the oil.
 Keep your fluids up.  Don't be a tailgater.  But don't be afraid of your van.