Kilgore Trout is correct when he says these engines do not blow head gaskets, or rarely do. When they do there is always an underlying problem rather than a material failure of the gasket itself. Nearly every time it is due to one of three things.
1. A coolant system failure that draws a steam void in the upper block. When this happens, a cylinder head warps (famous in aluminum cylinder heads), causing a gap between either the gasket, and the head or the deck. When that happens it is just a matter of time before the gasket gets worn away in that location. Fluids can mix or enter the cylinder, cylinder gases can enter the coolant, and very low cylinder pressure is typically seen in the affected cylinders.
2. Cylinder pressure goes up to the point the head bolts are stretched and the heads lift. This is most often seen in supercharged motors that don't use cylinder head studs or are running very high boost and not using lockwire o-rings. This problem is like problem one only much worse because the more cycles that occur, the more the bolts stretch, the more the gap widens. Fluids eventually start leaking past the gasket, even mixing sometimes (If you find antifreeze in your oil you get to replace every bearing in your rotating assembly - yippee!). Also cylinder gases are forced into the cooling system, displacing coolant, which causes overheating and a high probability of causing problem #1 all on its own. Due to the inconsistent pressures seen in the affected cylinder, detonation is much more likely to occur which can lead to catostrophic engine failure.
3. Another possibility for failure is improper torquing or torque sequencing, but then that's not really the fault of the gasket is it?
Technically none of these failures is a head gasket blowing out anyway. It has been repeatedly demonstrated in teardowns that these gaskets are extremely durable. I have seen several occasions where even under detonation severe enough to cause a forged piston or rod to fail, the head gasket will be completely unharmed.
So yes, Kilgore Trout is absolutly right, these cars don't blow gaskets just because of bad gaskets. It is a failure somewhere else in the system that leads up to a gasket failure. But in any case the situation is never good and always expensive. It nearly always results in a complete teardown, and mandotory decking and thorough inspection of the cylinder heads. Fortunately gasket failures are easy to spot by the many symptoms already mentioned elsewhere in this thread.
how does this sort of thing happen? how did you resolve the problem?
