2002 Dodge Stratus - I want to add water and antifreeze but when I try to turn the radiator cap, it turns but wont come off. Were do I add fluid?

Open the container of antifreeze. Using a separate EMPTY gallon-size container, pour out HALF of the contents into the empty container, making sure not to spill any. Now, FILL the newly filled container with tap water. Fill the rest of the antifreeze with water, also. Now, you are ready to add antifreeze to your vehicle! Simply locate the radiator cap, (Don't touch it if it's hot!!) and unscrew it. Pour the desired amount of your mixed antifreeze into the radiator. Remember not to do this without proper knowledge!

Both if so equipped (has a radiator cap). First top off radiator, then run to operating temp and add to reservoir until at the proper level. Test drive several miles, recheck reservoir.

Do a Compression Test on the Engine and see if you have a Blown Head Gasket. Chances are that is what is causing the Overflow... Exhaust Pressure is getting into the Cooling system

Hello there and welcome to fixya
Checking your radiator fluid:
Every modern vehicle has a Radiator fluid overflow compartment that is translucent so you can see where the coolant level is without removing the cap. On the side of the compartment there is a full line and an add line. the coolant should be between the two lines. If it's below the add level add 50% water/coolant to the full level.
The green line is the full line, the red line is the add line in the picture.
If you don't have antifreeze but you need fluid, add distilled water,not ordinary tap water, so mineral deposits won't build in the radiator and cause corrosion or blockage. However, you should keep the correct ratio of water and coolant to prevent corrosion and for the highest level of overheat or freeze protection.
To check the fluid IN your radiator
you will need to remove the radiator cap. DO NOT remove the radiator cap while the engine is hot. The contents are under pressure and many people have gotten severe burns by removing the radiator cap when it is too hot.
Notice the word "caution" on the cap in the picture.
It goes on to say the contents are under pressure.
IF you have no choice, but to remove the cap when hot, use a towel and remove it slowly to release pressure before you get the cap off.
The fluid in the radiator should be at the top of the radiator.

Make sure you keep 50% water/coolant mixture in the radiator. Some people put more antifreeze in during the winter, but never put more than 70% coolant. It will reduce it's ability to carry heat away from the engine and prevent corrosion.

Drain the radiator while the coolant is cold. Open the radiator drain plug at the bottom driver side, where bumper meets lower rail, and drain the fluid into a 5-gallon container. If it refuses to open or broke, remove the plastic cover at passenger side and disconnect the lower radiator hose. Do not forget to open the coolant cap, which allows air to enter the radiator core. With all the fluid emptied, refill the radiator tap or with distilled water, leave the cap open, and run the engine until it reaches operating temperature. The goal here is to get the thermostat open, diluting what coolant remains in the engine but the water will start boiling, and burn you out.
Or you can run the engine to get hot but not up to the boiling point. In this case the Flush won't be perfect, but you decrease the danger to burn out. Repeat the drain/refill procedure, until you will get a clear discharge.Repeat the drain and refill procedure two more times with distilled water. The tap water contains chlorine and will corrode the radiator and the cooling system. To fill the radiator, it is recommended to ad 30% volume distilled water to 70% volume concentrated Antifreeze. If you flush the system and rinse with water you must add only 30% water to the antifreeze. There is more water trapped inside the engine compartment, because the thermostat is closed. Make sure to have a coolant density tester. When you finish one of 5 balls must sink, that indicates that you reached 50/50 strength. That means 50% Prestone and 50% Water, which will provide to your car a -34F degree FREEZE-UP Protection , and +265F degree BOILOVER protection. Make sure to open bleeding valve to discharge air pockets from the cooling system. Add coolant.The next day, while engine is cold open the radiator cap, and test the strength of coolant. If it is not quite right, then siphon coolant from the radiator and add antifreeze, or distilled water as necessary. Start the Engine. Untwist the coolant bleeding nipple. If there will be a jet or stream of coolant, that means the water pump is working and is O.K., and there are not air pocket left in the cooling system.
Good Luck.

Does your car have a cap or a sealed unit? You don't want a sealed unit. You want to be able to check your water.Push down and Twist the cap off when cold, not hot, fill it up with coolant, 50/50 mix, and fill up the expansion tank. It says coolant on it. The car will balance itself out. Check the water in your battery while you are at it. It dries out too. Then check the brake fluid, power steering fluid, and oil. That should keep you busy next Saturday. Hope this helps.

its a drain plug. You can just pull off the bottom radiator hose if you want this will drain the radiator pretty good as well. Let a garden hose run in the radiator to the water runs out bottom clear put hose back on and add the antifreeze top off with water. Bleed the system of air.

Ok well there are two issues here the boiling and the potential for the transmission to be harmed by the contamination of the tranny fluid by antifreeze. First A/T fluid is not going to harm the coolant system in the least, however antifreeze in the trans. fluid will harm the automatic transmission get the tranny flushed as soon as possible , Change out the thermostat then refill radiator using 50% water 50 % antifreeze ( premixed in container) fill radiator then run the car without radiator cap add coolant as needed, put you radiator cap on and wait 5 - 10 minutes until car comes up to operatimg temp. you must observe the engine to make sure the electric radiator fan comes on after the car runs for at least ten minutes if it does not the problem is the usually the radiator fan relay or the fan coolant temperature sensor last in rare cases the fan itself. As for the air bleed usually letting the car run with the radiator cap off for ten to fifteen minutes will do it just make sure you don't remove the radiator cap when the car is hot 2nd degree burns usually hurt.

CHECK ANTIFREEZE IN RADIATOR.IF LOW ADD COOLANT.CHECK FOR LEAKING RADIATOR HOSES AND WATER PUMP HOSE.ALSO CHECK RADIATOR FOR LEAKS.IF ALL GOOD NO RADIATOR LEAKS.REPLACE THERMOSTAT.IF STILL OVER HEATS AFTER REPLACING THERMOSTAT .CHECK COOLING FANS FOR OPERATION AND COOLANT SENSOR.ALSO CHECK TO MAKE SURE WATER PUMP WEEP HOLES IS NOT LEAKING.BECAUSE A BAD WATER PUMP CAUSES OVERHEATING ALSO.

it is located on the radiator looking cap near oil cap... 2 bolts both 10mm. disconect all hoses to radiator cap ... on 2.4 liter engine // dont forget to bleed the system after you will the system