Yes, I agree. I also just drained all of the fluid out of the sump - a nice light brown/rust colored oil/water mix and a lot of it. I suspect most of the contents of the radiator was in there- this may also have contributed to the apparent good compression as the fluid level in the sump was very high? I also suspect a cracked block or sizable hole between the cooling water and oil sides of the block? With the sump plug out and all the fluid drained, I just tried pouring water into the top of the radiator and, as I suspected it would, the water flowed directly out of the sump plug hole at the same rate I was pouring it in! That means a big flow path - just wanting to know if there may be something less terminal going on or if anyone has seen something like this before?