• 2015

Radiator Replacement – 2005 Chrysler 300

Cooling system maintenance is essential for the long service life of its major components; namely, the water pump, heater core and the radiator. Failing to replace the coolant at the recommended intervals and/or adding the wrong coolant can lead to component failure. This corrosion can cause damage to the water pump seals and/or leaks in the radiator, requiring replacement of the damaged component.

cooling-system-schematicEngine Cooling System Flow – 5.7L


2 – BYPASS (Thermostat Closed – High Flow; Thermostat Open – Low Flow)




The primary purpose of the cooling system is to maintain engine temperature in a range that will provide satisfactory performance and emission levels under all expected driving conditions. This is done by circulating coolant throughout the engine to absorb excess heat. This hot coolant also flows through the heater to warm occupants in cold weather. This excess heat is then transferred when the coolant flows through the radiator.

When the engine is cold, the thermostat (which is a temperature-sensitive valve) is closed, preventing coolant flow through the radiator. Once the engine reaches operating temperature, the thermostat opens, allowing coolant flow through the radiator and the entire cooling system.


coolingTestingIconCoolant concentration should be checked when any additional coolant is added to the system or after a coolant drain and refill. The coolant mixture offers optimum engine cooling and protection against corrosion when mixed to a freeze point of -34°F to -50°F. A hydrometer can be used to test coolant concentration.

A hydrometer will test the amount of glycol in a mixture by measuring the specific gravity of the mixture. The higher the concentration of ethylene glycol, the larger the number of balls that will float in the hydrometer, and the higher the freeze protection (up to a maximum of 60% by volume of glycol).


To determine if coolant is flowing through the system (and the thermostat is opening when the engine temperature reaches normal), perform this simple test:

When the engine is cold, remove the pressurized radiator cap.

Remove a small amount of coolant.

Start the engine and allow it to idle until the engine reaches operating temperature. The thermostat should open and you should see coolant flow when you look down the filler neck of the radiator.

An alternate test method (and less preferred) is to start the engine when it is cold, allow it to idle until the normal operating temperature is reached and then feel the upper radiator hose. If it is hot, coolant is flowing. But, just because coolant is flowing doesn’t mean that the thermostat is operating properly.

During normal operating conditions, the thermostat closes a bit when the coolant temperature drops, then opens all the way when the temperature increases. Thermostats can stick closed even though it is a rare occurrence. Thermostats can also stick open. If the thermostat is stuck wide open, the coolant can never reach operating temperature.

If the coolant temperature is always below operating temperature as indicated on the temperature gauge on the instrument panel (usually there is a colored zone indicating where the needle should be during normal operation), or if you can’t get any heat, there’s a problem. The Check Engine light will illuminate.


Beyond normal and low coolant temperatures, let’s discuss the situation when the coolant temperature is too high. This is usually the result of a coolant leak. A common source of a coolant leak is a water pump seal failure, but coolant can also leak at a hose connection, hose fittings, heater core or from the radiator.

Radiator leaks can be the result of several conditions: cracks in the radiator tank, bad seams —where tank and core are joined together —corrosion, or a puncture. Regardless of the cause, the radiator will have to be replaced. Let’s review these procedures using the first generation Chrysler 300 equipped with the 5.7L HEMI® engine as our example.

Disconnect the negative battery cable before beginning any service work.

Drain the cooling system and remove the upper radiator hose.

Remove the upper radiator closure panels (these are the plastic panels that lay across the front edge of the engine compartment between the grille and front crossmember).

Disconnect the radiator fan electrical connector and remove the fan assembly.

NOTE: Notice that there is ample room between the radiator and the engine as this car has a forward mounted engine compared to the transverse layout seen on most modern vehicles.

Raise the vehicle in order to remove the lower splash shield, lower radiator hose and lower condenser mounting bolts. Then, lower the vehicle.

Remove the mounting bolts from the two upper radiator mounting brackets, then remove the brackets. The LH (driver side) radiator mounting bracket is shown here.


CAUTION: The mounting bolts use a thread locker; use hand tools to remove these bolts.

Remove the upper condenser mounting bolts and separate the condenser assembly from the radiator.

Tilt the radiator toward the engine, lift it up and remove it from the vehicle.

When re-installing the radiator, or installing a new unit if necessary, position the radiator correctly into the engine compartment. Seat the lower rubber isolators, which are attached to the bottom of the radiator, into the mounting holes in the lower radiator support. Tilt the radiator toward the grille, then install the two radiator mounting brackets and bolts. Tighten the mounting bolts to 106 in.-lbs. Next, position the condenser on the radiator and install the upper radiator mounting bolts. Tighten the bolts to 50 in.-lbs.

Raise the vehicle. Install the lower condenser bolts (tighten the bolts to 88 in.-lbs), then install the lower radiator hose and clamp. Lower the vehicle.

To finish the installation procedure, install the radiator fan and connect the radiator fan electrical connector. Install the upper radiator hose. Align the hose to prevent interference with the accessory drive belt and engine. Install the upper radiator closure panels. Connect the negative battery cable.

Finally, fill the radiator with the correct coolant/water mixture. Using the correct coolant is imperative. Turn the engine on, allow thermostat to open and drive the car until it reaches the normal operating temperature. Be sure that the engine does not overheat. Turn the engine off, check the coolant level and check for any leaks.




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