Since replacing the cooling system (New Rad, Rad Cap, Hoses, Thermostat, and complete flush of system) last November I've been losing about a quart of coolant or a bit more each week. The Ram runs fine, never overheats, heat works after driving a mile, and no relevant codes. Finally got a pressure tester today and first tested the rad cap (16 lbs)- goes to 12psi then holds at 10 for 5 minutes. Checked the old rad cap I'm not using and that one goes to 10psi then holds at 9. Put tester on the overflow (no cap on rad for 02) and pumped it up to 13psi and checked for leaks at rad, hoses including heater, water pump, and overflow tank. pressure holds steady with no drop after 5-10 minutes so guess that rules out head gasket thankfully. Found only one slight leak, a drip where one of the heater core hoses in the engine bay has a connector pipe joining 2 hoses with pressure clamps. A drop forms and will drip after 2-3 minutes onto the frame rail so its pretty slow leaking.

Would this be enough to need to top up as much as I am needing to each week?
Pic of drop forming in middle of circle between two clamps/hoses:

 

Have you ruled out the heater core itself? Currently my issue right now and burning through quite a bit of coolant.

 

The logical thing to do is to fix the leak you found and see if that takes care of it.

Not sure of the Ram setup but the cooling system in my Dak (4.7) is rated at 21 psi max. Best just to pump it up to max and stick a piece of cardboard underneath, then wait for a while for the drips. If still losing after fixing, go get a block tester as u may have a hg issue. If u pull plugs and one looks steam cleaned, that would be the cylinder where u have a hg leak.

If your heater core is leaking you should smell coolant and exp foggy windows.

 

Good comments and recommendations. Hopefully you won't have any more leaks after fixing that fitting.
Have you had an engine overtemp recently?
Your testing has not ruled out head gasket or water pump. Let us know if you still get leaks and we can look at some other tests.

 

Heater core checks out ok, no inside leaks, foggy windows, or coolant smell.
Didn't want to go at or over the 16psi with the tester as instructions said not to if cap is rated at 16. I can't rule out a bad tester as the rad caps are popping air early so didn't want to go over around 13psi. Haven't had an overheat happen. Will fix the small leak at the heater hose junction and see what happens.

With the rad caps do they usually popoff air at the rated psi or a few pounds early? My new in November one is a 16lbs one and popped at 12 and holds steady at 10.

 

Should pop at the rated pressure. If it doesn't, cooling system efficiency is compromised.

 

Went to the Parts store today to pick up a rad cap for the Grand Caravan as the one on there had failed completely, no pressure would hold. So go to the parts counter to get a new one and its a 16lbs one like the Ram. As I was returning the tool I asked to test the new one as I suspected a possible bad gauge on the tool that was under reading the psi. Tested some new ones and the all popped air at 12 psi like my newer ram one did. So, seems like the gauge is under reading by 4 psi and the Ram rad cap is good and I pressure tested the Rams cooling system at 17psi not the shown 13psi, with only the heater hose connection leaking (will be changing that and report back).

Disappointing that the gauge didn't read right, and not an inexpensive tool deposit as it was $220, more than most tool rental deposits. It was an "OEM" branded tester :