What I always maintained was that VW's are cheap cars.  They did not
get that way by VW putting any extra bits on, particularly expensive
brass bits like the thermostats.  VW made millions of these engines,
and probably spent $5 each for this thermostat and flap valves.  VW
seemed to think that it was worth the millions.  Who am I to argue
with them?  My truck lacked almost everything else, but this bit they
chose to keep.

BTW, this flap version is quite simplified from the version my original
motor had -- a ring that moved into place to block the inlet of the
big cooling fan.  THAT version must have really added to the cost of the
engine!  VW didn't leave it out, either, but they certainly figured out
how to cost-reduce it.

Put all the bits on the engine VW thought to include.  They may have left
some good bits off, but I doubt anybody could acuse them of gratuitously
adding things that weren't necessary.

malcolm