I've never worked on the 2.4 liter but I have changed a couple different temp sensors.
I think the part I marked as red is the temp sensor and the part marked yellow is what it screws into. It appears to be a pressed in part but I'm not sure why the o ring would be part of that.
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I tried to do some random searching but couldn't find out what it's called, if it's easily replaceable or if whatever it was pressed into needs replaced.