I noticed a coolant leak a little while back, and after some searching, I found it on the passenger side of the engine, against the firewall.

There are two metal hoses along the firewall, and the bottom one has a T-junction. At the bottom of the T is a brass nut. After cleaning the area up to get rid of the excess crap, I ran the engine and could see that the coolant appears to be leaking from the brass nut.

I'm not sure where to go from here. Is it ok to try to tighten the nut to see if that does the job, or will I need to disassemble the area and replace something?

I've attached some pictures for clarification



That little brass nut back there on the left seems to be leaking



Closer view


Closest view. After I cleaned up the area around the nut, and then refilled my coolant, I started the engine. Then, while the engine was running, I could see small droplets of coolant appearing near the nut.