Re-torqueing the head bolts: will this work?

This may seem like a dumb question, but I have to ask. I changed the water pump and thermostat plus flushed the cooling system in my girlfriend’s 300 diesel (turbo engine with 200K on it) a month ago. It now shows just the very smallest wisp of oil in the expansion tank. There is probably less than one drop worth of it in there, and it is definitely oil NOT transmission fluid. (I blotted some up with a paper towel and it is not red.)

I know what this means: head gasket time. But there is no coolant in the oil, in fact the cooling system holds pressure in it overnight (strange?). There is no coolant in the transmission fluid either. In fact, there is no coolant loss at all. The car does run warm, about 95-100 degrees in hot weather with the air conditioning on.

But I was wondering if there is ANY chance at all that re-torqueing the head bolts might even have ANY chance at sealing it back up? Is it worth trying, or do I even have to worry about this small of an amount of oil? I hear about diesel’s leaking, but I always assumed that means external, not internal leakage.

Thanks for the help everyone!