Joachim in Houston, TX wrote:

"..the waterpump on my 90 seized up yesterday with nary a warning . .
. ."

Which brings to mind "Water Pump Lubricants," a class of coolant
additive products I've seen marketed for decades.  I have no idea if
they help, hinder, or just hit the pocket book.  I've never seen any
test data nor much of anything written about them.  Does anyone have
any information about whether or not they help?
John