Nasty Engine Failure after Rebuild

[Hal Taylor <taylor@domain.elided>]

Well, my spider, Strega, is off the road and in the shop (leaving me
without an easy way to get to work, naturally).

Here's the scenario: driving along, in bumper-to-bumper traffic, I
looked and the mirror and noticed what appeared to be some smoke coming
from the tailpipe.  Recently, a puff of smoke from oil consumption would
not have been surprising, but I just had a top-end rebuild (head,
pistons, liners) done less than 6 months/10k miles ago.  So I watch it,
and notice that it's getting worse and worse, so I'm wondering if a
valve seal failed or something.  I'm almost home, and get off the
freeway, and I'm now seeing HUGE CLOUDS behind me.  The car is running
ok, and gauges are normal, so I keep heading home, figuring I'll drive
it to the shop Monday AM.  Then, the temperature gauge starts climbing
rapidly, and before long, the warning light is on and the gauge is
pinned.  I limp the last mile or so home.

Next morning, the situation is ugly.  I note that there's no coolant in
the radiator, so I add some.  Then I see if it'll run.  It sounds like a
detuned deseil for a few seconds, then stalls.  I check the oil.  Ut oh:
a pasty emulsion of 5/30 and antifreeze.  This is where I come to the
conclusion that the head gasket was gone.

So I tow it to the guy who did the rebuild.  He looks at it, and calls,
asking me to recap the sequence of events.  He sounds incredulous, and
then tells me that it looks to him like the headgasket is gone (I hadn't
shared my diagnosis), and that the headgasket only fails a result of the
car overheating.  So he wants to know if something else (like a lack of
coolant) caused the overheat, which in turn caused the headgasket to
fail (although, he says, it could be that the head itself cracked).

Now, I'm fairly attentaive to the needs of my car, and had hoped for my
rebuilt engine to last me quite awhile.  I'd come back at his specified
mileage so he could retorque the head bolts, had the oil changed
religiously, and watched the coolant.

I'm fairly certain that the "smoke" that I saw initially was a result of
the head gasket failure, well before the engine overheated.  Does anyone
out there have any opinions on how common/possible this may be? What
about the mechanic's responsibility to me after the rebuild?  I can't
help wondering if he's looking to blame the overheating for the
headgasket so that the problem is my responsibility, for not tending to
some (nonexistant, I'm fairly certain) cooling system problem...

Comments?

Hal Taylor
'86 spider veloce "Strega" (morta)
Venice CA (in case Fred has advice)

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