Need help identifying a doohickey

While removing the driver’s side cylinder head from my '88 Dakota, I damaged some sort of mechanism attached to the heater hose.

I don’t know what it is, can’t seem to find it in Haynes, and I’d appreciate help IDing it to see if I “really need” it or not.

Description: on the heater hose line leaving the block (uncertain if inlet or outlet), the hose goes into this mechanism, and a separate hose goes out to the heater core. The thing has plastic inlet and outlet for the hose, and a circular metal item of ~2" dia sits atop the plastic, with a vacuum line exiting the top center of the metal.

What is it? Do I need to replace/repair, or can I get decent performance without? (I wish I had my digital camera!)

ADDITIONAL INFO: There seems to be a throttle valve extending into the coolant flow to/from the heater core, actuated by a vacuum plunger, such that it constricts flow when vacuum is supplied to the doohickey. Hope that helps!

That sounds like a heater control valve. If there are 4 hoses connected the hoses act as a bypass whether the heater is on or off. When the heat is on water flows through the heater core and when off the water is diverted at the valve and returns to the engine directly. If only 2 hoses the valve just dead heads the flow from reaching the heater core.

I concur with RodKnox’s analysis of this. I’ve had several cars that have had a valve just like yours. How is it damaged? If you have decent heat and it’s not leaking, you can probably just ignore it for the winter, but when summer comes, your heat may not ever entirely turn off if this valve doesn’t work.