A million thanks for all the responses so far. The compression test results are in, and while they look promising, they do more to cloud the issue than they do to solve it. I don't know how the cylinders are numbered on these engines, so I'll list the values from left to right, standing at the FRONT of the van, facing the engine. Rear Bank = 195 ~ 200 ~ 199 PSI Front Bank = 208 ~ 201x ~ 200x PSI I put an "x" where the suspected cylinders would be. This is where the oily mess appears where the cylinder head mates with the engine block. Again, I don't know the origin of the oily grime, but it does not appear to be coolant. The plugs looked fair, they seem to be the original NGKs that came from the factory. Idiot had no problem dumping $4,000 on new brakes, shocks, struts, motor mounts, any everything else the mechanic wanted to sell him, but he declined spark plugs when the dealer suggested them. Strangely, the two plugs where I noted the "x" (suspected bad cylinders) appeared to be cleaner than the rest, and the one at the end of the block had rust on the threads and smelled of coolant. While this isn't proof that the head gasket is bad, it's not a comforting observation either. Is it possible that there would be a bad head gasket, but not show up in a compression test? I should note that we are at 6,500 feet elevation here, so the compression values are a fair bit lower than what would be measured at sea level.