Here's what happens when poor quality head gaskets leak - water in the cylinder, but that's not all. The water corrodes the metal surfaces of both the block and cylinder head, meaning that the surface is no longer flat and will not make a seal with new gaskets unless these mating surfaces are re-milled. You can mill the heads, but you can't re-mill the block. So what you end up with is basically a ruined engine. For another $100 in better quality gaskets, this would have been prevented. This inexpensive (Hino) diesel was only 5 years old and obviously had automotive gaskets.