I have a 2006 GC with about 130K on it. I have never serviced the cooling system. A few weeks ago it began to overheat and I added a couple quarts to the overflow tank. Problem solved. Last night it began overheating again. I opened the radiator and added about a gallon and a half. Problem again solved.

I suspected a leaking water pump but when I looked at it, I can see no evidence of a leak. I am seeing no water drips or evidence of leaks on the driveway.

Where is my coolant going?

 

If there's no obious leaks it's either dripping on the exhaust or you may have a leaking head gasket allowing coolant in the cylinders. What to do? Check for milky oil and black dots in the coolant. Connect a coolant system pressure tester and do a pressure leak down test.

 

I agree, get a pressure tester and see where the coolant is leaking from.

 

See my possibly related thread below - it may be what you are experiencing:

https://dodgeforum.com/forum/dodge-c...lant-leak.html