Yesterday a HEAVY drip of antifreeze suddenly appeared under my engine.
When I removed the plate that covers the pushrod tubes and started the
engine I saw that the source of the leak seemed to be a low spot at the very
center of the head gasket (thick "rubber" gasket under the head)as the area
around the very visible drip was dry with no moisture trails leading to it.
There was also a small patch of "rust" color where the gasket meets the head
around the area of the drip. All other areas of the gasket were pristeen. No
hoses or other fittings in the area showed any signs of leakage.
  This surprised me as, except for a very slight oil leak I have had for
years, there was no indication of an impending failure (like a slow
antifreeze leak). It went from bone dry to a gusher. Is it common for a head
gasket to fail this suddenly? This appears to be a simple case of replacing
the gasket but could I be wrong in my diagnosis? Could this be the dreaded
head problem I have heard about (there is only 65,000 miles on the van)?

   I looked through the Bentley and the gasket replacement seems pretty
straightforward but my paranoia tells me that a corollary to Murphy's Law is
in effect here (If you believe everything is under control you appearently
do not realize the true situation). Hense this posting.

   Given my description is my diagnosis correct?

   Is there anything I am leaving out?

   Is there anything else I should check before I pull the head?

   Once the head is pulled, is there anything I should look for or do "as
long as I am in there"?

   What parts should be replaced (like pushrod tubes?) should be replaced to
avoid having to pull the head again at a later date?

   Any advice, observations, wisecracks, ect. would be much appreciated.