Looking to find what this sensor is, it is leaking a ton of coolant and we need to fix it.
Engine is a 72 olds 350 in a 1949 98

 

I would suggest removing that "stack" of reducers and find one that fits the manifold and is sized to the brass one. I think you really need to get the temperature sensor down into the flow of the coolant.
Be sure to clean the threads and use Teflon pipe sealer to seal the threads. Be sure to tighten them adequately. Install the reducer first (adequately tightened), then the brass adapter. Good luck.

 

I agree there should be only one bushing for that sender, but maybe the installer used what he could easily find to adapt the sender to the port in the manifold.

And that brings up this observation - I see an EGR valve in the picture, so that intake manifold (and maybe the entire engine?) is a 1973-later vintage. Dunno if that would have any impact on the sender to intake size compatibility.

 

Must be for an aftermarket water temperature gauge ? Like the others said all you probably need to do is get rid of that stack of adapters and it will probably stop leaking.

 

I would revisit the throttle return spring. Its attachment the intake manifold looks like a disaster waiting to happen.

 

Good thing there's a lock washer on your vacuum tube screw!

And X2 on that return spring placement.

 

Does the car have an aftermarket electric fan?