Re: Nasty Engine Failure after Rebuild

[Simon Favre <simon@domain.elided>]

I hate to say it, but you probably should have pulled over at the
first sign of increasing smoke. "Limping home" with an Alfa blowing
that much smoke is asking for trouble. The most common casues for
such smoke are an oil leak dumping onto the exhaust, which can cause
an engine fire and/or siezed mains, or a coolant leak, also onto the
exhaust, which can cause a cracked head. In this case, by the time 
the gauge jumped up, the damage may already have been done. Usually,
when a head gasket goes, the early signs are coolant that smells
like gasoline, and coolant getting pushed out of the radiator into
the overflow bottle. When the bottle is full, the coolant will get
pushed out into the engine bay. You might also have just blown a hose
or a water pump, and not noticed the smoke in time.

While it is possible for a new head gasket to fail, it is usually
possible to keep it from destroying the rest of the motor. If you
had pulled over at the first sign of trouble, and checked under the
hood, you might have found something to tell you there was a serious
problem. Obviously, I'm not looking under the hood of your car right
now, so it's entirely possible your diagnosis is correct. A careful
inspection of the gasket and the head surface are in order. The
problem is, once a head is cracked, it's hard to tell if it was the
cause or the result of an overheat. A crack into the exhaust port is
fairly common. This will produce some exhaust smoke, and the exhaust
will smell of coolant. If you lost the coolant thru a liner seal, the
result will be emulsified oil, and overheating, but no smoke, at
least until the head gasket has failed completely. If the head surface
has a large pit right at the sealing ring around one liner top, then
you might well have a case against the mechanic. Laying the gasket on
the head surface and checking to see if any head imperfections line up
with the critical gasket surfaces is a good precaution during assembly.

I have also heard that the recent crop of head gaskets don't work as
well as the old ones. When the head is pulled, if the glue on the head
gasket never really set, then you might have a case for a defective 
gasket. Unfortunately, if the thing overheated as badly as you say, the
glue might be melted or fried away, destroying the evidence.

Try to work with the mechanic on this. Look for evidence, not fault.

Hal Taylor wrote:

>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.
... {SNIP}

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