Chrysler Repair: Sebring cooling: coolant not drawn out of overflow bottle, head gasket leak, radiator cap

Question
my car overheated awhile back and since then i have replaced everything in the cooling system it seems, radiator, water pump, timing belt, thermostat, radiator cap, overflow bottle, and fan.  my problem now is the coolant keeps going into the overflow but it doesn't come back over to the engine so you have to keep putting coolant in the engine.  what would cause this to happen?  also what is the proper level of coolant to put in the vehicle?  I really like the car but right now i am scared to drive it very far, because i don't want to get stuck on the side of the road.  Also it had the exhaust test done on it awhile back and they said there was no exhaust in the cooling system.  the car is a 2000 sebring convt.

Answer
Hi Robin,
The failure of the expanded coolant to return to the system from the overflow bottle is an indication of a less than air-tight cooling system. It appears that you have done all the replacements that are appropriate.
While you have tested for exhaust in the cooling system it still remains possible for there to be a leak of the cooling system into the oil system or a leak of the cooling system into a cylinder which does not produce sufficient fumes to be detected. I would check to make sure that your oil is transparent and not cloudy. I would also when starting the engine from a protacted cooldown/overnight rest immediately observe for white smoke coming from the tailpipe and which when allowed to condense on you hand has a smell of antifreeze.
Either of those would be tell-tail of a head gasket leak. Such a leak may have caused your original overheating experience. Also listen for sound of premature bubbling coming from the engine or radiator as the engine warms up but has not reached operating temperature.
It may be that if there is a minor leak of one of the two head gaskets, assuming that you have the V-6 engine, that 'simply' loosening slightly and then retightening the head bolts on both banks of cylinders will eliminate the problem.
When you write back let me know how the temperature gauge is behaving and whether there is any sign of overflow from the bottle after you have started the cold engine with a full radiator and with the coolant level in the bottle within the max/min lines, which would also corroborate an over-pressurized system due to an exhaust gas leak.
Roland