Dodge Neon overheating

DLIGHTHART

MEMBER
DODGE NEON

I have a 4 door 1996 Dodge Neon with approximately 55,000 miles on it. It had a 117,000 miles on it but last year it had the motor replaced (I had just gotten it from work and the engine blew). The motor they put in they said had 42,000 miles on it. It had spent its whole life in IL until May of this year. Then we moved to FL and I have to drive 80 miles a day round trip to work. It overheated last week and I had to have it towed home. We have put a radiator init and a new thermostat but it is still overheating. Tested the fans on a 12v battery and they were working. One of the guys at work said there is a thermostat for the fans because when it overheats no, the fans don't kick on. Where is this other thermostat located or is there something else I should be looking at. Don't have much money and can't afford to take it in. Help!

4 Replies

MIKEYBDMAN

MECHANIC
623 POSTS

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.