Engine Overheating

I have a 2002 Liberty and my engine seems to be overheating. I recently had the radiator changed because it was leaking, but it overheats when I sit in traffic, with the heat on. Could this be a fan, or maybe a thermostat? Thanks

Shorted coolant, or a bad coolant bleed procedure could cause the thremostat to stick.

Is your electric cooling fan coming on when you're sitting in traffic? On the Grand Cherokees there is an occasional problem with the fan relay. I don't know where it's located on the Liberty...you may want to have a read in the GC section to compare.

Oh...and did it overheat in traffic before you had the radiator replaced?