2004 Chrysler Sebring Coolant Overflow

As fred_dot_u stated, the reason your car's coolant is overflowing as it is is due to the radiator cap no longer functioning properly. My sister's car, a 2004 Dodge stratus...same vehicle, was in to a mechanic recently for engine performance issues, however, the mechanic also noted that he, for whatever reason believed the engine was overheating when it was not and claimed the boiling over coolant was a result of that. In reality what was occuring was that the coolant was absorbing more heat from the engine after it was turned off and, unable to maintain the pressure normally required by the cooling system, was overfilling the reserve tank.

All in all a radiator cap replacement should fix your problem as it did on my sister's. Best of luck to you.

Those cars are notorious for head gasket failures, and depending on the leak location you may not get water moving into the oil. The cylinder pressure even before ignition is about 10 times higher than the coolant pressure, so the tendency is for combustion gas to leak into the coolant, forcing coolant out through the overflow.

You also could have an air pocket that wasn't been completely removed when you refilled the system. Many of the Chrysler vehicles of that era required an additional accessory to be attached to the top of the coolant reservoir when you filled it in order to build enough elevation head to push the water into all of the air pocket areas.