Upsit2mitch@How do I change the thermostat? - 2002 Dodge Intrepid

Two bolts on the thermostatic housing connected to a thick hose.

---

2.7L Engine

1. Disconnect negative cable.
   CAUTION Do not remove pressure cap with the system hot and under pressure because serious burns from coolant can occur.
   
2. Drain cooling system.
3. Remove radiator lower hose from thermostat housing.
4. Remove nuts from heater tube flange studs.
5. Loosen starter bolt at heater tube bracket.
6. Pull heater tube out of thermostat housing and position out of the way.
7. Remove bolt and two studs.
8. Remove thermostat housing, O-ring and thermostat.
9. Remove thermostat housing bolts.

To install:

1. Clean gasket sealing surfaces.
   NOTE Install thermostat with the bleed valve located at the 12 o'clock position, between tabs on seal.
   
2. Install thermostat and seal into thermostat housing .
3. If removed, install two studs.
4. Install thermostat, thermostat housing and O-ring and bolt. Tighten attaching bolts to 105 inch lbs.(12 Nm).
5. Lubricate new heater return tube O-ring with coolant.
6. Position heater return tube flange over two studs. Install nuts.
7. Tighten retaining nuts to 53 inch lbs.(6 Nm).
8. Tighten starter bolt to 40 ft. lbs. (54.3 Nm).
9. Connect the lower radiator hose to the thermostat housing. Install hose clamps.
10. Refill cooling system.
11. Inspect for leaks.
12. Connect negative cable.

3.2L & 3.5L Engines

1. Disconnect negative cable.
   CAUTION Do not remove pressure cap with the system hot and under pressure because serious burns from coolant can occur.
   
2. Drain cooling system.
3. Raise vehicle on hoist.
4. Disconnect electrical connectors from engine oil and power steering pressure switches.
5. Disconnect radiator and heater hoses from thermostat housing.
6. Remove thermostat housing bolts.
7. Remove housing, thermostat, and gasket.
   NOTE The OEM thermostat is staked in place at the factory. To ensure proper seating of replacement thermostat, carefully remove the bulged metal from the thermostat housing using a suitable hand held grinder. It is not necessary to restake the replacement thermostat into the thermostat housing.
   

To install:

1. Position gasket on thermostat and housing.
2. Install thermostat housing, gasket and mounting bolts onto block. Tighten attaching bolts to 105 inch lbs. (12 Nm).
3. Install radiator hose.
4. Install bypass hose.
5. Connect electrical connectors from engine oil and power steering pressure switches.
6. Connect negative cable.
7. Fill cooling system.
8. Inspect for leaks.
9. Lower vehicle on hoist.

The thermostat is operated by a wax filled chamber (pellet) which is sealed. When heated coolant reaches a predetermined temperature the wax pellet expands enough to overcome the closing spring and water pump pressure, which forces the valve to open. Coolant leakage into the pellet will cause a thermostat to fail open. Do not attempt to free up a thermostat with a screwdriver. Thermostat diagnostics is included in power train control module's (PCM) programming for on-board diagnosis. The malfunction indicator light (MIL) will illuminate and a diagnostic trouble code (DTC) will be set when an -open too soon- condition occurs. Do not change a thermostat for lack of heater performance or temperature gauge position, unless a DTC is present. For other probable causes,. Thermostat failing shut is the normal long term mode of failure, and normally, only on high mileage vehicles. The temperature gauge will indicate this.
The engine cooling thermostats are a wax pellet driven, reverse poppet choke type. The thermostats have an air bleed located in the thermostat flange. The air bleed allows internal trapped air during cooling system filling to be released. The thermostat on the 2.7L and 3.5L engines are located on the lower left side of engine, near the front. The thermostat on both engines are on the inlet side of the water pump.
The thermostat is designed to provide the fastest warm up possible by preventing leakage through it and to guarantee a minimum engine operating temperature of 88 to 93°C (192 to 199°F). The thermostat also will automatically reach wide open so it will not restrict flow to the radiator as temperature of the coolant rises in hot weather to around 104°C (220°F). Above this temperature the coolant temperature is controlled by the radiator, fan, and ambient temperature, not the thermostat.
Back to Top