I have a 2002 sebring, 2.7 liter engine, dash always reads normal, but when you drive the car and then turn it off the overflow boils and pops reservoir hose off and shoots hot coolant, just replaced the coolant flange hoping this would fix the issue, but it still is doing it, I also bled all air out of the line before driving

hi it sound like it is the fan switch or the wires have come off the switch

Jeff, Check the attached links for your 2.4 belt routing,instruction and guides, Good luck
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Repair Guides Engine Mechanical Components Accessory Drive Belts 2...
How to Change Serpentine Belt on 2002 Chrysler Sebring
http://www.serpentinebeltdiagram.com/serpentine-belt-diagram-2001-chrysler-sebring-4-cylinder-24-liter-engine-alternator-and-air-conditioner-with-dohc-engine-02236

Could be a defective radiator cap, or a leaking head gasket.

is it boiling or bubbling big difference but sounds like there's air getting in system or exhaust gases more info would be a big help is car overheating ?

Hi there the common problem found with your car is one thermostat sizes and will not let the water pass threw this in turn will cause boiling in the head and overflow bottle .2nd have a look at water hoses around engine and radiator they leak a bit , if no leaks are found my guess thermostat

it could very well be a bad gauge. when it shows the engine to be overheated or at the least very hot, check the actual temp at the water outlet where the upper radiator hose attaches to the engine. use a non contact thermometer to check the temp so as not to get burned in the process. if the thermometer reads way different than the gauge, the gauge is bad.

Answer could be a faulty thermostat,or it could be a sign that your head gasket is about to blow ,or last of all your timing could be out of sync.

Answer 2 from Inventus: It means your cooling system is funtioning properly. In a system having a coolant recovery tank, coolant in the radiator is always up to the brim, hot or cold. There is negligible or no air space. When coolant in the radiator expands sufficiently due to warming from the engine, it will squeeze past the pressure cap's bottom seal and flow into the recovery tank. (If no provision for such expansion was present, the expansion would rupture the radiator or your hoses.) Only coolant within the radiator is under pressure, and because of this pressure (together with the elevated boiling point that the "anti-freeze" permits), it normally does not boil. But once past the pressure cap's bottom seal, the overflow is at atmospheric pressure and therefore boils.
This boiling is usually unnoticed after a short, i.e., local, trip because the cooler coolant already in the recovery tank quenches it. But after some highway driving the influx of more hot overflow heats up all the coolant in the recovery tank to the (unpressurized, i.e., "natural") boiling point.
As the engine cools when shut off, the contracting coolant in the radiator sucks back coolant from the recovery tank. Fluid in the recovery tank should never be below the "full hot" or "full cold" marks, lest air be sucked in.
-- BETTER ANSWER ==
Your cooling fans are not turning on. It is not normal for your overflow tank to boil like that. It is true that your radiator is overflowing into the reserve tank, but that means yourr adiaotor is boiling. Check for blown fuses or relays for your cooling fans. IF theya re fine. run your engine for about 15 minutes and drive. When you temp level is at normal operating temp open your hood with the engine runing and see if your fans are on. If they are, then you may have a bad thermostat or a plugged radiator, or a bad water pump. If the fans are not on, get your cooling fan switch replaced if your car has one. Check your temp sending sensor

Did you compare what your dash gauge read when it was acting up and compare it to the manual gauge at the same time? I know you said you used the manual gauge and it read fine so if you get a proper reading out of the manual gauge and an improper reading out of the dash gauge then your dash gauge needs addressed.

it sounds like one of several problems radiator needs flushed , water pump is bad or going, thermostat is bad, pin hole in one of the hoses, cracked head, hole in radiator, hole in heater core.if core is leaking you will notice water on the floor inside the car on pasenger side. if radiator has hole when you fill radiator with coolant it will leak froom fins sometimes only when hot. thermostat bad your car will read hot and or cold always. if stuck open cold, if stuck closed hot, after about 15 20 mins of running engine will cause radiator to boil over to over flow tank.never open radiator cap when engine is hot :) burn hazard.if pump is bad or going will notice gauge reads hot intermittent or always. will boil in to overflow tank. if head is cracked will notice water comming from side of engine block or in oil when you change oil. if radiator needs to be flushed will notice scale or gunk on radiator cap
(if you think you need help or do not have tools to perform please take to a machanic)

the thermostates on the 3400 engines are late because the fans kick in at the last moment. if you run your ac on you will notice that the gauge stays in front of the half mark or right on the half mark. that is because when you turn on your ac your fans will kick in earlier and stay on the whole time the ac is on. if you run your car with the heat on or nothing on that leaves the late thermostate to kick in verus you turning on your ac and it by passes the thermostates and runs the fans once the engine gets at at lest 120 deg. i use to have a 2002 and i had the same problem. this will keep your engine cooler. also if you don't want your air on just turn on your windshield defrosters (not the back windshield) and that helps keep your engine cool because your defrosters use your air compressor which is really your ac. so it still kicks the fans on earlier.