[Walt Fricke]

Melted in a candle flame?

The engine oil temperature thermostat operates on the expansion of wax due to heat. As the oil going through the thermostat heats up, the wax expands and forces a plunger out of the unit. The force this plunger exerts opens the "valve" to the engine mounted oil cooler. When cold, the oil goes directly to the engine oil passages (starting with the big one heading to the rear of the car along the top of the engine). All the oil flow to the engine goes by the pressure piston, which is sort of down in its tube below the level of the oil gallery, if memory serves.

If this is wax from this source, you'd expect some would get into some of the smaller oil passages, causing problems. And some would be bypassed (starting cold in the winter, for instance) back into the sump, where it would end up on the scavenge side filter.

I'd guess this didn't get through the oil pump - I'd suppose it would look much different, as it would be in thinner and more uniform shapes.

But that's just my guess. The part which is pressed outward in the thermostat looks sort of like a nail with a round head. It amazed me that pressure on something of so small a diameter as the shank of this piece could be so forcefully moved.

If examination doesn't show anything suspicious about your oil thermostat, put it in the freezer for a while. Then toss it into a pan of boiling water, and watch to see if the "nail" starts to emerge. If it doesn't move, the internal unit has failed. They can be replaced, though opening the internal thermostat isn't as straight forward as is opening the external thermostat - which the '71s didn't have, I think - certainly not the T model.

But if it is wax, I'd think you could deform it with your fingers. I'm pretty sure these cases were not cast using the lost wax process.