Coolant Leak. What is this part?

Hello all. Identified a coolant leak while doing an oil change today. The first piece of this is the thermostat housing (RH70, from what I can tell), but I'm not sure what the heck the piece it's connect to is called. Trying to find what I need on rockauto, but am failing.

Any help is appreciated, thanks!

P.S. Yep, rusty as crap underneath. Year-round DD for me since '05.

I would go to tasca ford parts and look at the cooling system diagrams to get the name/number

DSG2003Mach1 said:

I would go to tasca ford parts and look at the cooling system diagrams to get the name/number

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Thanks man, I'll give that a shot.

Edit: quick look wasn't successful as far as the diagrams IDing it but I'm tired so will try again tomorrow with a cup of coffee.

YELOSNK said:

Thanks man, I'll give that a shot.

Edit: quick look wasn't successful as far as the diagrams IDing it but I'm tired so will try again tomorrow with a cup of coffee.

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Its the whole unit the thermostat housing. Are you looking go replace the whole unit?

There's an o-ring in there that might just need to be replaced. But the housing itself is probably a dealer item only.

is this it?
1996-2004 Mustang Thermostat Housing - 4V - LMR.com

Lots here: Cooling

Including these...