Hi,
Go under the van and be prepared to drop some coolant!! in your face!!! (he
he)
Have everything you need before doing so (towel, new parts, tools),
remove the old one (It'secured by a "C" clip) just a bit, when this one is
almost out, have the new one in hand and very close the the old one.
Pull the old one and insert the new one very quick! Put a small amount of
grease on the new O-ring to help this one go IN easily. Put the NEW C-clip
IN.

To bleed:
Start engine, Just open the thermostat bleeding screw for a few second and
look for air bubble. (they won't be any!) The 87 will self bleed IF there
is any air pocket.

The coolant loss is minimal if you go fast when changing the sender.
I would say...half cup of coffee.

Don't woory if you find that the new sender is somewhat loose, it's normal!
Good luck, Ben
http://www3.sympatico.ca/huotx/engine1.htm