Dodge Nitro. Manual - part 518

REMOVAL-3.7L 

Fig. 45: Identifying Power Cord, Block Heater & Core Hole 
Courtesy of CHRYSLER LLC 

1. Drain cooling system. See STANDARD PROCEDURE.  

2. Raise vehicle on hoist.  

3. Detach power cord plug from heater. 

1 - POWER CORD
2 - BLOCK HEATER
3 - CORE HOLE

 

2007 Dodge Nitro R/T 

2007 ENGINE Cooling - Nitro

  

4. Loosen screw in center of heater. Remove heater assembly.  

INSTALLATION 

INSTALLATION-3.7L 

Fig. 46: Identifying Power Cord, Block Heater & Core Hole 
Courtesy of CHRYSLER LLC 

1 - POWER CORD
2 - BLOCK HEATER
3 - CORE HOLE

 

2007 Dodge Nitro R/T 

2007 ENGINE Cooling - Nitro

  

1. Thoroughly clean core hole and heater seat.  

2. Insert heater assembly (2) with element loop positioned upward .  

3. With heater seated, tighten center screw securely to assure a positive seal. 

4. Connect power cord to heater.  

5. Lower vehicle.  

6. Fill cooling system. See STANDARD PROCEDURE.  

SENSOR-ENGINE COOLANT TEMPERATURE 

DESCRIPTION 

DESCRIPTION 

The Engine Coolant Temperature (ECT) sensor is used to sense engine coolant temperature. The sensor 
protrudes into an engine water jacket. 

The ECT sensor is a two-wire Negative Thermal Coefficient (NTC) sensor. Meaning, as engine coolant 
temperature increases, resistance (voltage) in the sensor decreases. As temperature decreases, resistance 
(voltage) in the sensor increases. 

OPERATION 

OPERATION 

At key-on, the Powertrain Control Module (PCM) sends out a regulated 5 volt signal to the ECT sensor. The 
PCM then monitors the signal as it passes through the ECT sensor to the sensor ground (sensor return). 

When the engine is cold, the PCM will operate in Open Loop cycle. It will demand slightly richer air-fuel 
mixtures and higher idle speeds. This is done until normal operating temperatures are reached. 

The PCM uses inputs from the ECT sensor for the following calculations: 

For engine coolant temperature gauge operation through the bus communications  

Injector pulse-width  

Spark-advance curves  

ASD relay shut-down times  

Idle Air Control (IAC) motor key-on steps  

Pulse-width prime-shot during cranking  

O2 sensor closed loop times  

CAUTION: To prevent damage, the power cord must be secured in its retaining 

clips, and not positioned so it could contact linkages or exhaust 
manifold.

 

2007 Dodge Nitro R/T 

2007 ENGINE Cooling - Nitro

  

Purge solenoid on/off times  

EGR solenoid on/off times (if equipped)  

Leak Detection Pump operation (if equipped)  

Radiator fan relay on/off times (if equipped)  

Target idle speed  

REMOVAL 

REMOVAL-3.7L ENGINE 

Fig. 47: Removing/Installing MAP Sensor/ECT Sensor 
Courtesy of CHRYSLER LLC 

 

2007 Dodge Nitro R/T 

2007 ENGINE Cooling - Nitro