Hello. Owning a vanagon for any length of time will make you either broke,
or wrench proficent. The radiator switch is straight forward. Not sure of
the socket size, but it is a deep socket.Channel lock plyers can be used.
It is not installed too very tight. Never seen  this switch go bad myself.
The symptoms are a fan that dosent switchon or  a fan that wont switch off.
Early vanagons have a switch that cuts on and off at different tempatures
than the later vanagons. Only buy a few degrees though. Dont know which
switch is best.Same thread size on both switches. Put a thread sealer on
the switch and screw it back in.

The water temp 2 switch is the same. Dont put it in too tight as the
threads are aluminum. Dont know if this matters with brass threads on
aluminum.Be prepared for a small amount of coolant to come out. I usually
have the replacement all ready to go. When the old comes out, the new goes
right in 2 seconds later.I think it has a washer. Not sure.