Engine Cooling System & Automatic Transmission Cooling System: Overview Chrysler Crossfire I

Scheme 3

A conventional cross-flow aluminum core radiator (4) is used to cool the engine. The Coolant Recovery Reservoir (1) is equipped with a Coolant Level Sensor. The Coolant Level Sensor in the Coolant Recovery Reservoir notifies the driver if there is insufficient coolant in the system by illuminating the low engine coolant warning lamp in the Instrument Cluster. An Electric Cooling Fan (2) is activated by the Radiator Fan Control Module. The cooling system is also equipped with an additional electric Coolant Circulation Pump. The pump is used to keep the passenger cabin warm by circulating coolant through the heater core when the engine is off.

Scheme 4

On vehicles equipped with a Supercharger, there are additional cooling system components. The Charge Air Cooler, Charge Air Cooler Radiator, Charge Air Cooler Circulation Pump, and all related hoses are also part of the cooling system. The Charge Air Cooler Radiator is a conventional cross-flow aluminum core radiator. The Charge Air Cooler Radiator mounts in front of the A/C Condenser, and behind the front fascia. The Charge Air Cooler Circulation Pump is mounted to the side of the Charge Air Cooler Radiator. The pump is used to circulate coolant between the Charge Air Cooler and the Charge Air Cooler Radiator. It operates independently from the engine cooling system. The only common link is the Coolant Recovery Reservoir. Both systems use the Coolant Recovery Reservoir as their source of coolant.

OPERATION

Scheme 5

1. When engine is cold: Thermostat (6) is closed, cooling system has no flow through the radiator (7). The coolant flows through the engine, heater core (3), coolant recovery reservoir (1) and an internal engine by-pass.
2. When engine (2) is warm: Thermostat (6) is open, coolant flows through the radiator (7), heater core (3), coolant recovery reservoir (1) and by-pass.

The cooling systems primary purpose is to maintain engine temperature in a range that will provide satisfactory engine performance and emission levels under all expected driving conditions. It also provides hot coolant for heater, and cooling for automatic transmission fluid. It does this by transferring heat from engine metal to coolant, moving this heated coolant to the radiator, and then transferring this heat to the ambient air. The cooling system is also equipped with an additional electric coolant circulation pump. The pump is used to keep the passenger cabin warm by circulating coolant through the heater core when the engine is off.

Scheme 6

Supercharged vehicles (if equipped) have additional cooling system components. The Charge Air Cooler (2), Charge Air Cooler Radiator (3), Charge Air Cooler Circulation Pump (4), and all related hoses make up the charge air cooler cooling system. The charge air cooler system operates independent of the engine cooling system. The Charge Air Cooler Circulation Pump is mounted to the side of the Charge Air Cooler Radiator. The pump is used to circulate coolant between the Charge Air Cooler and the Charge Air Cooler Radiator. The only common link between the two systems is the Coolant Recovery Reservoir (1). Both systems use the coolant reservoir as their source of coolant.

DESCRIPTION

The cooling system is designed around the coolant. The coolant must accept heat from engine metal, in the cylinder head area near the exhaust valves and engine block. The coolant then carries the heat to the radiator where the tube/fin radiator can transfer the heat to the air.

The use of aluminum cylinder blocks, cylinder heads, and water pumps require special corrosion protection. Use coolant approved to MB 325.0, such as Mopar part number 05066386AA, or an equivalent Extended Life Coolant with the HOAT inhibitor system. This coolant offers the best engine cooling without corrosion when mixed with 50% ethylene-glycol and 50% distilled water to obtain a freeze point of -37°C (-35°F). If it loses color or becomes contaminated, drain, flush, and replace with a fresh properly mixed coolant solution.

Coolant flows through the engine block absorbing the heat from the engine, then flows to the radiator where the cooling fins in the radiator transfers the heat from the coolant to the atmosphere. During cold weather the antifreeze/coolant prevents water present in the cooling system from freezing within temperatures indicated by mixture ratio of coolant to water.

A pellet-type thermostat controls the operating temperature of the engine by controlling the amount of coolant flow to the radiator. The thermostat is opened when the engine temperature reaches 195°F (90°C). When opened, the thermostat allows engine coolant to flow to the radiator. This provides quick engine warm up and overall temperature control.

Scheme 7

The same thermostat is used for winter and summer seasons. An engine should not be operated without a thermostat, except for servicing or testing. Operating the engine without a thermostat can cause the following problems

1. Longer engine warm-up time
2. Unreliable warm-up performance
3. Increased exhaust emissions
4. Crankcase condensation

This condensation can result in sludge formation.

The wax pellet is located in a sealed container at the spring end of the thermostat. When heated, the pellet expands, overcoming closing spring tension and water pump pressure to force the valve to open.

Scheme 8

1. Remove the thermostat from the engine. «(Refer to COOLING/ENGINE/ENGINE COOLANT THERMOSTAT - REMOVAL)»(ref-250623-S13260624812007031500000) .
2. Suspend the thermostat in a container of water. CAUTION: Never use a welding torch or soldering torch as the sudden introduction of heat alters the structure of the metal!
3. Heat the container and thermostat. NOTE: The rate of increase should not be more than 1°C to 2°C/min from about 8 °C below the start of opening of the coolant thermostat.
4. Measure the temperature of the water.
5. Heat the water to the temperature specified on the thermostat. Allow the thermostat to fully open, and then measure the distance of the stroke.
6. If the specifications are not achieved, install a new coolant thermostat.

Scheme 9

1. Remove the air cleaner housing. «(Refer to ENGINE/AIR INTAKE SYSTEM/AIR CLEANER HOUSING - REMOVAL)»(ref-250615-S26276682392007031500000) or «(Refer to ENGINE/AIR INTAKE SYSTEM/AIR CLEANER HOUSING - REMOVAL)»(ref-250616-S02809968752007031500000) .
2. Partially drain the cooling system. «(Refer to COOLING/ENGINE/COOLANT - STANDARD PROCEDURE)»(ref-250623-S38251009092007031500000) .
3. Disconnect the upper radiator hose. NOTE: The thermostat housing and the thermostat are serviced as an assembly. The thermostat cannot be serviced separately.
4. Remove the thermostat housing retaining bolts and remove the thermostat and housing from the engine.

The pressure chamber keeps the coolant free of trapped air, provides a volume for expansion and contraction, and provides a convenient and safe method for checking and adjusting coolant level at atmospheric pressure. It also provides some reserve coolant to cover minor leaks, evaporation or boiling losses. The overflow chamber allows coolant recovery in case of an overheat.

Scheme 10

1. Disconnect the negative battery cable.
2. Partially drain the cooling system. «(Refer to COOLING/ENGINE/COOLANT - STANDARD PROCEDURE)»(ref-250623-S38251009092007031500000) .
3. Disconnect the small coolant hose at the coolant recovery reservoir (4).
4. Disconnect the large coolant hose at the bottom of the coolant recovery reservoir (3).
5. Disconnect the coolant level sensor harness connector (2) at the coolant recovery reservoir.
6. Disconnect the coolant overflow hose (1).
7. Remove the two retaining nuts (2) and lift the coolant recovery reservoir from the engine compartment.

Scheme 11

1. Disconnect the negative battery cable.
2. Partially drain the cooling system. «(Refer to COOLING/ENGINE/COOLANT - STANDARD PROCEDURE)»(ref-250623-S38251009092007031500000) .
3. Disconnect the small coolant hose at the coolant recovery reservoir (4).
4. Disconnect the large coolant hose at the bottom of the coolant recovery reservoir (3).
5. Disconnect the coolant level sensor harness connector (2) at the coolant recovery reservoir.
6. Disconnect the charge air cooler coolant hose (2) from the coolant recovery reservoir (1).
7. Disconnect the coolant overflow hose (1).
8. Remove the two retaining nuts (2) and lift the coolant recovery reservoir from the engine compartment.

The engine coolant temperature sensor provides an input to the powertrain control module (PCM). As coolant temperature varies, the engine coolant temperature sensor resistance changes, resulting in a variable input voltage to the PCM.

When the engine is cold, the PCM will demand slightly richer air-fuel mixtures and higher idle speeds until normal operating temperatures are reached.

The engine coolant sensor input also determines operation of the radiator fan.

Scheme 12

Scheme 13

Scheme 14

1. Disconnect the negative battery cable.
2. Partially drain the cooling system. «(Refer to COOLING/ENGINE/COOLANT - STANDARD PROCEDURE)»(ref-250623-S38251009092007031500000) .
3. Remove the engine cover (1). Grasp both corners of the engine cover, and pull up firmly.
4. Disconnect the engine coolant temperature sensor harness connector (1).
5. Pull up on the engine coolant temperature sensor retaining clip (1) and slide the engine coolant temperature sensor out of the housing.
6. Remove the engine coolant temperature sensor from the engine.

Scheme 15

Scheme 16

Scheme 17

Scheme 18

Scheme 19

1. Disconnect the negative battery cable.
2. Partially drain the cooling system. «(Refer to COOLING/ENGINE/COOLANT - STANDARD PROCEDURE)»(ref-250623-S38251009092007031500000) .
3. Remove the engine cover. Grasp both corners of the engine cover and pull up firmly. «(Refer to ENGINE - REMOVAL)»(ref-250615-S24998160682007031500000) or «(Refer to ENGINE - REMOVAL)»(ref-250616-S16649150172007031500000) .
4. Remove the air pump tube retaining bolts (2).
5. Remove the air pump tube assembly from the engine (1). «(Refer to EMISSIONS CONTROL/AIR INJECTION/AIR PUMP INLET TUBE - REMOVAL)»(ref-250614-S38752648592007031500000) .
6. Release the tension on the accessory drive belt.
7. Remove the accessory drive belt from the accessory drive belt idler pulley.
8. Remove the supercharger idler pulley upper retaining bolt (1) and lower retaining bolt (2).
9. Remove the supercharger idler pulley.
10. Remove the accessory drive belt idler pulley (2) to gain access to the engine coolant temperature sensor (1).
11. Disconnect the engine coolant temperature sensor (1) harness connector.
12. Pull up on the engine coolant temperature sensor retaining clip (1) and slide the engine coolant temperature sensor out of the housing.
13. Remove the engine coolant temperature sensor from the engine.

The Crossfire has a cross flow type radiator (4). The main radiator core is made of aluminum, and the side tanks are made of plastic (3).

Note. Handle the radiator with care, plastic tanks while stronger than brass, are subject to damage.

Scheme 20

Scheme 21

Scheme 22

Scheme 23

1. Disconnect the negative battery cable.
2. Remove the radiator fan. «(Refer to COOLING/ENGINE/RADIATOR FAN - REMOVAL)»(ref-250623-S19590179442007031500000) .
3. Drain the cooling system. «(Refer to COOLING/ENGINE/COOLANT - STANDARD PROCEDURE)»(ref-250623-S38251009092007031500000) .
4. Remove the air cleaner inlet tubes.
5. Disconnect the upper radiator hose (1).
6. Disconnect the lower radiator hose (2).
7. Disconnect the coolant recovery reservoir hose (1).
8. Disconnect the transmission cooler line (3) located on the right side of the radiator (automatic transmission only). «(Refer to COOLING/TRANSMISSION/TRANS COOLER LINES - REMOVAL)»(ref-250623-S12028723372007031500000) .
9. Disconnect the transmission cooler line (1) located in the middle front of the vehicle (automatic transmission only). Using a suitable tool, grasp the radiator hold down clamps (2) and pull up to remove the clamps from the mounting holes.
10. Remove the condenser retaining bolts (1) from the radiator support.
11. Carefully lean the radiator back toward the engine.
12. Gently lift and remove the radiator from the vehicle.

The pressure cap performs two tasks in a closed cooling system. The pressure cap must allow the cooling system to build pressure during engine operation, and allow the cooling system to loose pressure when not operating.

With the engine operating, the pressure cap must allow the cooling system to operate at higher than atmospheric pressure. This increased pressure raises the boiling point of the coolant, thereby allowing the cooling system to operate more efficiently. However, under excessive pressure, 110 kPa +/- 14 kPa (16 psi +/- 2 psi) the cooling system will overcome the spring pressure in the pressure cap and allow engine coolant to flow into the reservoir. This pressure relief will continue until the pressure is reduced and the spring in the pressure cap can return to its normally closed position.

With the engine not operating, the pressure cap must allow the cooling system to loose pressure and recover engine coolant. This recovery is accomplished through the use of a lighter spring in the pressure cap. As the hot engine coolant cools, it creates a vacuum in the cooling system. As this vacuum is created, it pulls the vacuum valve open and allows engine coolant to be pulled back into the engine from the coolant reservoir tank. This continues until the system pressure is equalized, and the vacuum valve is then returned to its normally closed position.

The water pump is a die cast aluminum housing with a swept vane impeller. It attaches directly to the timing chain cover. The pump is driven from the crankshaft by a single serpentine drive belt. The water pump impeller is pressed onto the rear of a shaft that rotates in bearings pressed into the housing. The water pump seals are lubricated by the engine coolant.

A centrifugal water pump circulates coolant through the water jackets, passages, intake manifold, radiator, cooling system hoses, and heater core. The coolant absorbs the heat generated when the engine is operating. The water pump is driven by the crankshaft via the serpentine drive belt.

Scheme 24

Scheme 25

Scheme 26

1. Disconnect the negative battery cable.
2. Drain the cooling system. «(Refer to COOLING/ENGINE/COOLANT - STANDARD PROCEDURE)»(ref-250623-S38251009092007031500000) .
3. Remove the air cleaner inlet tubes (2).
4. Remove the engine cover (1). Grasp both corners of the engine cover, and pull up firmly.
5. Remove the radiator fan. «(Refer to COOLING/ENGINE/RADIATOR FAN - REMOVAL)»(ref-250623-S19590179442007031500000) .
6. Remove the accessory drive belt. «(Refer to COOLING/ACCESSORY DRIVE/DRIVE BELTS - REMOVAL)»(ref-250623-S19655078942007031500000) .
7. Remove the belt tensioner. «(Refer to COOLING/ACCESSORY DRIVE/BELT TENSIONERS - REMOVAL)»(ref-250623-S11396632562007031500000) .
8. Disconnect the lower radiator hose (2).
9. Disconnect the coolant by-pass hose (1).
10. Remove the generator. «(Refer to ELECTRICAL/CHARGING/GENERATOR - REMOVAL)»(ref-250642-S27922636232007031500000) .
11. Remove the water pump pulley (2).
12. Remove the accessory drive belt idler pulley (1).
13. Remove the water pump retaining bolts and the water pump.

Scheme 27

Scheme 28

1. Remove the engine cover. Grasp both corners of the engine cover and pull up firmly.
2. Drain the cooling system. «(Refer to COOLING/ENGINE/COOLANT - STANDARD PROCEDURE)»(ref-250623-S38251009092007031500000) .
3. Remove the radiator fan. «(Refer to COOLING/ENGINE/RADIATOR FAN - REMOVAL)»(ref-250623-S19590179442007031500000) .
4. Remove the air pump tube retaining bolts (2).
5. Remove the air pump tube assembly from the engine (1). «(Refer to EMISSIONS CONTROL/AIR INJECTION/AIR PUMP INLET TUBE - REMOVAL)»(ref-250614-S38752648592007031500000) .
6. Rotate the belt tensioner counterclockwise and release the tension on the accessory drive belt.
7. Remove the accessory drive belt from the pulleys.
8. Carefully release the wrench tension on the belt tensioner.
9. Remove the supercharger idler pulley upper retaining bolt (1) and lower retaining bolt (2).
10. Remove the supercharger idler pulley.
11. Remove the accessory drive belt from the engine.
12. Remove the belt tensioner pulley and the belt tensioner. «(Refer to COOLING/ACCESSORY DRIVE/BELT TENSIONERS - REMOVAL)»(ref-250623-S11396632562007031500000) .
13. Disconnect the lower radiator hose (2).
14. Disconnect the coolant by-pass hose (1).
15. Remove the generator. «(Refer to ELECTRICAL/CHARGING/GENERATOR - REMOVAL)»(ref-250642-S27922636232007031500000) .
16. Remove the water pump pulley (2).
17. Remove the accessory drive belt idler pulley (1).
18. Relocate the oil cooler hose (3) clamp.
19. Remove the water pump retaining bolts.
20. Remove the water pump from the engine. Remove the oil cooler hose (3) from the water pump to the oil cooler tube.

Scheme 29

Note. It is normal for the water pump to weep a small amount of coolant from the weep hole (black stain on water pump body). Do not replace the water pump if this condition exists. Replace the water pump if a heavy deposit or a steady flow of engine coolant is evident from the weep hole. This indicates a shaft seal failure and pump must be replaced. Be sure to perform a thorough analysis before replacing water pump.

Inspect and replace the water pump if it has any of the following defects

1. Damage or cracks on the pump body (1).
2. Coolant leaks; if the seal is leaking, this will be evident by traces of thick deposits of dried coolant draining from the pump weep hole. A thin black stain below pump weep hole/passage is considered normal operation (2).
3. Impeller rubs against the engine front cover (3).
4. Excessively loose or rough turning bearing (3).

Scheme 30

1. Clean all gasket surfaces.
2. Position the water pump with a new gasket on the timing chain cover.
3. Install the water pump bolts in the correct positions. Tighten the bolts to 35 N.m (26 ft. lbs.).
4. Install the generator. «(Refer to ELECTRICAL/CHARGING/GENERATOR - INSTALLATION)»(ref-250642-S42543175232007031500000) .
5. Install the belt tensioner. «(Refer to COOLING/ACCESSORY DRIVE/BELT TENSIONERS - INSTALLATION)»(ref-250623-S40180305042007031500000) .
6. Install the water pump pulley (2) and bolts. Tighten the water pump pulley bolts to 10 N.m (89 in. lbs.).
7. Install the idler pulley (1) and bolt. Tighten the idler pulley bolt to 10 N.m (89 in. lbs.).
8. Connect the lower radiator hose (2) and coolant by-pass hose (1).
9. Rotate the belt tensioner counterclockwise and install the accessory drive belt.
10. Release the belt tensioner and remove the wrench.
11. Install the radiator fan. «(Refer to COOLING/ENGINE/RADIATOR FAN - INSTALLATION)»(ref-250623-S38275167602007031500000) .
12. Install the engine cover (1). Align the engine cover retaining clips to the rubber mounts, and push down firmly to connect engine cover to rubber mounts. NOTE: To ease the installation of the engine cover, apply a small amount of lubricant to the engine cover rubber mounts.
13. Install the air cleaner inlet tubes (2).
14. Connect the negative battery cable.
15. Fill the cooling system. «(Refer to COOLING/ENGINE/COOLANT - STANDARD PROCEDURE)»(ref-250623-S38251009092007031500000) .
16. Start the engine and check for coolant leaks.
17. Recheck the coolant level.

On vehicles equipped with a supercharger, there is an additional radiator used in the cooling system. The charge air cooler radiator, is a conventional cross-flow aluminum core radiator. The charge air cooler radiator mounts in front of the A/C condenser, and behind the front fascia. The charge air cooler circulation pump is mounted to the side of the charge air cooler radiator. The pump is used to circulate coolant between the charge air cooler radiator and the charge air cooler located beneath the supercharger. The charge air cooler radiator operates independently of the engine cooling system. The only common link is the coolant reservoir. Both systems use the coolant reservoir as their source of coolant.

The charge air cooler radiator operates similarly to the engine radiator. Hot coolant flows into the radiator from the charge air cooler. The coolant is then circulated through the radiator, where it is cooled. The coolant leaves the radiator, and is then pumped back to the charge air cooler.

Scheme 31

Scheme 32

Scheme 33

Scheme 34

Scheme 35

1. Remove the front fascia from the vehicle. «(Refer to FRAME & BUMPERS/BUMPERS/FRONT FASCIA - REMOVAL)»(ref-250611-S21043765322007031500000) .
2. Remove the nuts from the charge air cooler radiator (1) left and right mounting bracket studs.
3. Tilt the charge air cooler radiator away from the left and right mounting studs (1).
4. Lift the charge air cooler radiator out of the left and right lower rubber mounts (2).
5. Carefully remove the charge air cooler radiator from the vehicle.
6. Allow the charge air cooler radiator (2) to hang from the cooling hoses (1).
7. Remove the drain plug (1) from the charge air cooler radiator.
8. Drain the coolant out of the charge air cooler cooling system.
9. Disconnect the inlet coolant hose (2) and the outlet coolant hose (1) from the charge air cooler radiator.
10. Remove the charge air cooler radiator from the vehicle.

Scheme 36

1. Locate the upper mounting studs (1), and the lower rubber mounts (2) for the charge air cooler radiator.
2. Carefully install the charge air cooler radiator, and seat the radiator into the lower rubber mounts.
3. Tilt the charge air cooler radiator inward, and install the radiator onto the upper mounting studs.
4. Install the left and right charge air cooler radiator retaining nuts. Tighten the nuts to 10 N.m (89 in. lbs.).
5. Connect the inlet and outlet coolant hoses.
6. Refill the cooling system.

Scheme 37

The charge air cooler is used to reduce the temperature of the engines incoming air supply. The charge air cooler is mounted to the bottom of the supercharger, and is located between the cylinder banks. The charge air cooler is constructed of aluminum, and is detachable from the supercharger.

The purpose of the charge air cooler is to reduce the air inlet temperature thereby increasing air density thus producing an increase in engine efficiency. The charge air cooler operates as an air-to-water heat exchanger. The charge air cooler extracts heat from the incoming compressed air, leaving the supercharger. Transferring the heat in the air to the to the coolant in the charge air cooler. The hot coolant is then circulated to the charge air cooler radiator where it is cooled.

Scheme 38

Scheme 39

Scheme 40

1. Remove the engine supercharger (3). «(Refer to ENGINE/MANIFOLDS/SUPERCHARGER - REMOVAL)»(ref-250616-S24525864922007031500000) .
2. Remove the four charge air cooler flange bolts (2) from the supercharger housing.
3. Remove the two mounting bolts (4) from the supercharger housing.
4. Separate the charge air cooler from the supercharger.
5. Remove the charge air cooler flange gasket (1).
6. Remove the MAP sensor (1) from the charge air cooler.

The charge air cooler circulation pump operates independently of the engine cooling system. The only common link is the coolant reservoir. The circulation pump is operated by a pulsed 12 volt signal.

Scheme 41

Scheme 42

1. Remove the right front inner fender lining in order to gain access to the charge air cooler circulation pump.
2. Remove the charge air cooler circulation pump inlet hose (2).
3. Remove the charge air cooler circulation pump outlet hose (1).
4. Disconnect the charge air cooler circulation pump harness connector (2).
5. Remove the charge air cooler circulation pump mounting bolt (1).
6. Remove the charge air cooler circulation pump from the mounting bracket.

A single, serpentine style belt drives all of the engine accessories. The accessory drive includes an automatic tensioner, making adjustments unnecessary for the life of the belt.

Scheme 43

The accessory drive belt provides the link between the engine crankshaft and the engine accessories. Tension on the accessory drive belt is maintained by an automatic belt tensioner.

1. Crankshaft
2. A/C Compressor
3. Power Steering Pump
4. Idler Pulley
5. Generator
6. Water Pump
7. Tensioner

Scheme 44

The accessory drive belt provides the link between the engine crankshaft and the engine accessories. Tension on the accessory drive belt is maintained by an automatic belt tensioner.

1. Supercharger
2. Power Steering Pump
3. Automatic Tensioner
4. A/C Compressor
5. Crankshaft
6. Water Pump
7. Generator
8. Idler
9. Supercharger Idler