You give no specifics... How many miles? How much coolant are you losing??
Long ago I realized that the 'low' and 'high' marks on the coolant bottle really should be marked "cold" and "hot".
If, when the car is cold, you fill to the top mark, you will lose coolant when the car gets hot.
When cold, you want to be at or near the low mark (not below).
There is a dye that can be put in the coolant that shows up under UV light - to look for possible leaks. That may be your next step.

 

Thank you - for some reason I always get nervous posting and make basic mistakes like this. I appreciate everyone's grace for a long time reader who has not had many (knock on wood) issues with our Pacifica!

We are at 105,000 miles.

The Coolant loss is not significant, about once a week/week and a half we need to add a few ounces to match the exact parameters you mentioned, always after allowing the vehicle to fully cool down.

Thanks for the idea about the UV light kit - I'm looking at that now! We haven't had any puddling in the driveway and the Chrysler tech didn't see anything dripping while they were doing a live diagnostic.

With some more looking at the forums, this looks like it might be a bigger issue that has affected a number of people over different model years.

You give no specifics... How many miles? How much coolant are you losing?? (not a significant amount at a time)
Long ago I realized that the 'low' and 'high' marks on the coolant bottle really should be marked "cold" and "hot". (This is a great idea and simple)
If, when the car is cold, you fill to the top mark, you will lose coolant when the car gets hot. (We have been following this guidance)
When cold, you want to be at or near the low mark (not below).
There is a dye that can be put in the coolant that shows up under UV light - to look for possible leaks. That may be your next step. (I see a few options and will look into this)