Tom,
I would replace the water pump and thermostat. Make sure the thermostat is
genuine VW. This is a must. I highly recommend a German water pump also. I
have had a lot of trouble from the Italian made version.
While you have the old one out, compare the impeller-to-body clearances.
Hopefully you will see a huge difference between old and new.
--
Ken Lewis
http://neksiwel.20m.com/