1996 Dodge Neon Overheating
Fan control is accomplished in two ways.
The fan always runs when the compressor clutch is engaged.
The fan is also turned on by the temperature of the coolant which is sensed by the coolant temperature sensor. The coolant temperature sensor sends this signal to the engine controller which turns the fan on through the fan relay. Switching through the engine controller provides fan control for the following conditions:
Fan will not run when cranking engine no matter what coolant temperature is.
Fan will run when A/C clutch engaged and low pressure cutout switch is closed.
At vehicle speeds over 40 mph, fan will run only if coolant temperature reaches 230°F (110°C) and fan will turn off when temperature drops to 220°F (104°C).
At vehicle speeds under 40 mph, fan will run when coolant temperature reaches 215°F (102°C ) and fan will turn off when temperature drops 200°F (93°C).
To prevent steaming, the fan will run with engine at idle speed and only for three minutes , when ambient temperature is below 60°F (16°C) and coolant temperature is between 100-207°F (38-97°C).
NOTE: The engine coolant temperature sensor threads into the rear of the cylinder head.
REMOVAL
With the engine cold, drain coolant until level drops below sensor.
Disconnect coolant sensor electrical connector.
Remove coolant sensor.
INSTALLATION
Install coolant sensor.
Tighten to 18 Nm (165 in lb) torque.
Attach electrical connector to sensor.
Fill cooling system.
The cylinder head is the part of the engine that both the intake and exhaust attaches to. It sits on top of the engine block, and there is a valve cover on top of it. Usually that says something like 2.0L SOHC or something like that.
Suggested Repair
The radiator fans are controlled by the engine controller through the fan relay, using the coolant temperature sensor at the rear of the cylinder head, and also run when the A/C compressor clutch is engaged. With the engine cold, drain coolant below the sensor, disconnect it, and replace it if faulty; torque to 18 Nm (165 in-lb), reconnect it, and refill the cooling system. Also verify the fan relay and related wiring if the fans still do not come on at the specified temperatures.
Conversation Summary
A 1996 Dodge Neon continued overheating after a radiator and thermostat were replaced. The fans worked when powered directly but did not come on during overheating. The expert explained that fan operation is controlled by the engine controller and fan relay based on the coolant temperature sensor, plus A/C clutch engagement, and located the sensor at the rear of the cylinder head with removal and installation steps. The owner planned to pass the information to a relative and report the result.
