Thermostat housing exhaust passage?
 

So while fixing my coolant leak on the bottom of the thermostat housing, I noticed there is an exhaust passage that goes from the cylinder head/ engine block into the thermostat housing. What is the deal with that? Is it supposed to heat the housing to keep it from icing in cold weather?

It seems to dead end in a tapered passage inside the housing. The attached picture is taken looking at the bottom of the thermostat housing.

I did not expect to see exhaust soot in one of the thermostat passages! I am not sure how the exhaust routes to get there. Perhaps an EGR passage?

Have no idea, I just want to see more pics of the engine in the background.

Secondary air injection system

Interesting the would engineer such a short passage into the water neck.


The engine in the back is a 497 inch Chrysler Hemi with a Mooneyham 8-71. It is my old street race car that used to be fast long ago, but the new generation of cars are just in another league. It made 1122HP on C16 and 984 on pump gas with the boost turned down. 8.70's in the 1/4 on Hoosier street tires and 9.40's on pump gas.

Here is a pic I have with me, not very good quality though.

I have also wondered where it went. I can see its probably for air injection but where does it actually go? Does it go through the housing?

Best as I can tell it dead ends inside the housing. It must be to make sure the thermostat stays free of ice in extreme winter climates, I guess... Other ideas?