Here is what I have experienced on the leaking around the coolant level
sender:
1. The expansion tanks get hairlined cracks around the sender hole and leak.
2. The sender gets a stress crack in the side of it from someone putting it
on too tight (happens alot).
3. Both.

The senders I get are German (sometimes with the VW symbol on them).
The tanks I get are VW dealer overstock (little VW symbol on them or you can
tell where it was scratched off (?))

Bottom line, if you carefully inspect your tank with a magnifying glass
around the sender hole, and also inspect the sender under a good light with a
glass, you will find the problem.
Upon installing the sender, just remember that it is Plastic, going into a
Plastic Tank.  No need for 75 ftlbs of torque.  I will check today to see if
Bentley has a torque spec for this but if it does you should use a torque
wrench when installing.  I just snug it (mechanic's experience), not super
tight, as this can cause more problems than if it is a little loose.

My opinion,
Ken Wilford
http://www.vanagain.com
John 3:16
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