Engine Cooling: Other Saab 9-7X I

Reference Information

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

1. «Cooling System Connector End Views»(ref-268147-S39274932672007101800000)
2. «Powertrain Control Module Connector End Views»(ref-268121-S02268913102007101800000) for the 4.2L engine
3. «Engine Control Module Connector End Views»(ref-268122-S35122689362007101800000) for the 5.3L engine

Electrical Information Reference

1. «Circuit Testing»(ref-268113-S34300255622007101800000)
2. «Connector Repairs»(ref-268113-S12163038632007101800000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-268113-S21569870072007101800000)
4. «Wiring Repairs»(ref-268113-S39498775722007101800000)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List»(ref-268095-S39033231162007101800000)
2. «Scan Tool Data Definitions»(ref-268108-S41740513132007101800000)
3. «Scan Tool Output Controls»(ref-268108-S36201141602007101800000)

Circuit/System Verification

1. Idle the engine.
2. Command the cooling fan clutch to 10 percent.
3. Operate the engine at 2,000 RPM for 2 minutes. The fan should be quiet to indicate the clutch is disengaged.
4. Command the cooling fan clutch to 80 percent.
5. Operate the engine at 2,000 RPM for 2 minutes. The fan should be loud to indicate the clutch is engaged.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Fan Clutch Replacement»(ref-268147-S13596641922007101800000)
2. «Cooling Fan and Shroud Replacement»(ref-268147-S12673307262007101800000)
3. «Cooling Fan Relay Replacement»(ref-268147-S28535810922007101800000)
4. «Control Module References»(ref-268114-S32850434302007101800000) for replacement, setup, and programming

1. Ignition OFF, inspect the cooling fan and the drive belt for the following conditions: A cracked drive belt A loose or a worn drive belt A misrouted drive belt Oil leaks at the cooling fan clutch A free-spinning cooling fan A seized cooling fan clutch A broken cooling fan
2. Idle the engine.
3. Command the cooling fan clutch to 10 percent.
4. Operate the engine at 2,000 RPM for 2 minutes. The fan should be quiet to indicate the clutch is disengaged.
5. Command the cooling fan clutch to 80 percent.
6. Operate the engine at 2,000 RPM for 2 minutes. The difference between the fan speed and the desired fan speed should remain less than 1,000 RPM throughout the speed transition.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Fan Clutch Replacement»(ref-268147-S13596641922007101800000)
2. «Cooling Fan and Shroud Replacement»(ref-268147-S12673307262007101800000)
3. «Cooling Fan Relay Replacement»(ref-268147-S28535810922007101800000)
4. «Control Module References»(ref-268114-S32850434302007101800000) for replacement, setup, and programming

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

1. «Cooling System Connector End Views»(ref-268147-S39274932672007101800000)
2. «Powertrain Control Module Connector End Views»(ref-268121-S02268913102007101800000) for the 4.2L engine
3. «Engine Control Module Connector End Views»(ref-268122-S35122689362007101800000) for the 5.3L engine

Electrical Information Reference

1. «Circuit Testing»(ref-268113-S34300255622007101800000)
2. «Connector Repairs»(ref-268113-S12163038632007101800000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-268113-S21569870072007101800000)
4. «Wiring Repairs»(ref-268113-S39498775722007101800000)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List»(ref-268095-S39033231162007101800000)
2. «Scan Tool Data Definitions»(ref-268108-S41740513132007101800000)
3. «Scan Tool Output Controls»(ref-268108-S36201141602007101800000)

Engine OFF, verify the fan clutch is not binding by turning the fan by hand.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Fan Clutch Replacement»(ref-268147-S13596641922007101800000)
2. «Cooling Fan and Shroud Replacement»(ref-268147-S12673307262007101800000)
3. «Cooling Fan Relay Replacement»(ref-268147-S28535810922007101800000)
4. «Control Module References»(ref-268114-S32850434302007101800000) for replacement, setup, and programming

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

1. «Cooling System Connector End Views»(ref-268147-S39274932672007101800000)
2. «Powertrain Control Module Connector End Views»(ref-268121-S02268913102007101800000) for the 4.2L engine
3. «Engine Control Module Connector End Views»(ref-268122-S35122689362007101800000) for the 5.3L engine

Electrical Information Reference

1. «Circuit Testing»(ref-268113-S34300255622007101800000)
2. «Connector Repairs»(ref-268113-S12163038632007101800000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-268113-S21569870072007101800000)
4. «Wiring Repairs»(ref-268113-S39498775722007101800000)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. «Scan Tool Data List»(ref-268095-S39033231162007101800000)
2. «Scan Tool Data Definitions»(ref-268108-S41740513132007101800000)
3. «Scan Tool Output Controls»(ref-268108-S36201141602007101800000)

1. Idle the engine.
2. Command the cooling fan clutch to 10 percent.
3. Operate the engine at 2,000 RPM for 2 minutes. The fan should be quiet to indicate the clutch is disengaged.
4. Command the cooling fan clutch to 80 percent.
5. Operate the engine at 2,000 RPM for 2 minutes. The difference between the fan speed and the desired fan speed should remain less than 1,000 RPM throughout the speed transition.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Fan Clutch Replacement»(ref-268147-S13596641922007101800000)
2. «Cooling Fan and Shroud Replacement»(ref-268147-S12673307262007101800000)
3. «Cooling Fan Relay Replacement»(ref-268147-S28535810922007101800000)
4. «Control Module References»(ref-268114-S32850434302007101800000) for replacement, setup, and programming

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Engine Coolant Temperature Indicator Always On

Engine Coolant Temperature Indicator Always On

Engine Overheating

Engine Overheating

Loss of Coolant

Loss of Coolant

Electrical Information Reference

1. «Circuit Testing»(ref-268113-S34300255622007101800000)
2. «Connector Repairs»(ref-268113-S12163038632007101800000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-268113-S21569870072007101800000)
4. «Wiring Repairs»(ref-268113-S39498775722007101800000)

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Coolant Heater Replacement (LH6)»(ref-268147-S01661167412007101800000) or «Coolant Heater Replacement (LL8)»(ref-268147-S20005696822007101800000)
2. «Coolant Heater Cord Replacement»(ref-268147-S13023021502007101800000)

Engine Fails To Reach Normal Operating Temperature

Engine Fails To Reach Normal Operating Temperature

Tools Required

J 24460-01 Cooling System Pressure Tester. See Special Tools .

1. Remove the pressure cap.
2. Test the operation of the pressure cap. Refer to «Pressure Cap Testing»(ref-268147-S09122732982007101800000) .
3. Wash the pressure cap mating surface with water.
4. Use the J 24460-01 in order to apply pressure to the cooling system. See «Special Tools»(ref-268147-S09851013102007101800000) . Do not exceed the pressure cap rating.
5. The cooling system should hold the rated pressure for at least 2 minutes. Observe the gauge for any pressure loss.
6. Repair any leaks as required.

Coolant Filling Procedure

Note. The procedure below must be followed. Improper coolant level could result in a low or high coolant level condition, causing engine damage.

1. If a complete block drain was required, install the coolant heater or plug. Refer to «Coolant Heater Replacement (LH6)»(ref-268147-S01661167412007101800000) or «Coolant Heater Replacement (LL8)»(ref-268147-S20005696822007101800000) .
2. Install the lower radiator hose.
3. Using the J 38185 slide the clamp into the original position. See «Special Tools»(ref-268147-S09851013102007101800000) .
4. Lower the vehicle. IMPORTANT: Slowly add a mixture of 50/50 DEX-COOL antifreeze and deionized water to the cooling system through the top of the radiator until full. Refer to «Capacities - Approximate Fluid»(ref-268159-S19539682002007101800000) .
5. Install the radiator cap.
6. Remove coolant recovery reservoir cap.
7. Slowly add a mixture of 50/50 DEX-COOL antifreeze and deionized water to the cooling system through the coolant recovery reservoir. Refer to «Capacities - Approximate Fluid»(ref-268159-S19539682002007101800000) .
8. Fill the coolant recovery reservoir with the remaining coolant.
9. Install the coolant recovery reservoir cap.
10. Install the coolant air bleed hose to the throttle body.
11. Using J 38185 slide the coolant air bleed hose clamp back to the original position. See «Special Tools»(ref-268147-S09851013102007101800000) .
12. Start the engine.
13. Run the engine from 1,000-3,000 RPM in 30-second intervals until the engine reaches normal operating temperature.
14. Allow the engine to idle for 3 minutes before repeating the last step.
15. Shut the engine OFF.
16. Allow the engine to cool.
17. Top off the coolant recovery reservoir as necessary.
18. Rinse away any excess coolant from the engine and the engine compartment.
19. Inspect the cooling system for leaks.
20. Inspect the concentration of the engine coolant using J 26568 . See «Special Tools»(ref-268147-S09851013102007101800000) .

1. J 38185 Hose Clamp Pliers. See «Special Tools»(ref-268147-S09851013102007101800000) .
2. J 26568 Coolant and Battery Fluid Tester. See «Special Tools»(ref-268147-S09851013102007101800000) .

Note. The procedure below must be followed. Improper coolant level could result in a low or high coolant level condition, causing engine damage.

1. If a complete block drain was required, install the plug.
2. Install the outlet (lower) radiator hose.
3. Using J 38185 slide the clamp into the original position. See «Special Tools»(ref-268147-S09851013102007101800000) .
4. Lower the vehicle. IMPORTANT: Slowly add a mixture of 50/50 DEX-COOL antifreeze and deionized water to the cooling system through the top of the radiator until full. Refer to «Capacities - Approximate Fluid»(ref-268159-S19539682002007101800000) .
5. Remove coolant recovery reservoir cap.
6. Fill the coolant recovery reservoir with the remaining coolant.
7. Install coolant recovery reservoir cap.
8. Install the radiator cap.
9. Start the engine.
10. Run the engine at 1,000-3,000 RPM in 30 second intervals until the engine reaches normal operating temperature.
11. Allow the engine to idle for 3 minutes.
12. Shut the engine OFF.
13. Allow the engine to cool.
14. Top off the coolant recovery reservoir as necessary.
15. Rinse away any excess coolant from the engine and the engine compartment.
16. Inspect the cooling system for leaks.
17. Inspect the concentration of the engine coolant using J 26568 . See «Special Tools»(ref-268147-S09851013102007101800000) .

Radiator Cleaning

Note. The radiator fins are necessary for good heat transfer. Do not brush the fins. This may cause damage to the fins, reducing heat transfer.

1. Some conditions may require the use of warm water and a mild detergent.
2. Clean the A/C condenser fins.
3. Clean between the A/C condenser and radiator.
4. Clean the radiator cooling fins.
5. Straighten any damaged cooling fins.

Scheme 29

1. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(ref-268121-S41476428912007101800000) for the 4.2L engine or to «Air Cleaner Assembly Replacement»(ref-268122-S40840121412007101800000) for the 5.3L engine.
2. Remove the accumulator. Refer to «Accumulator Replacement»(ref-268096-S21231262572007101800000) .
3. Remove the coolant hoses from the coolant recovery reservoir and plug the hoses and the coolant recovery reservoir outlets with suitable plugs (2).
4. Remove the nut and bolt securing the coolant recovery reservoir.
5. Remove the coolant recovery reservoir.

J 38185 Hose Clamp Pliers. See Special Tools .

Scheme 30

1. Drain the cooling system. Refer to «Draining and Filling Cooling System (LH6)»(ref-268147-S30426788732007101800000) or «Draining and Filling Cooling System (LL8)»(ref-268147-S34710564872007101800000) .
2. Remove the air intake resonator. Refer to «Air Cleaner Resonator Outlet Duct Replacement»(ref-268122-S06780068422007101800000) .
3. Using J 38185 reposition the radiator inlet hose clamp (1) from the engine. See «Special Tools»(ref-268147-S09851013102007101800000) .
4. Remove the outlet hose from the engine.
5. Using J 38185 reposition the radiator inlet hose clamp (2) from the radiator. See «Special Tools»(ref-268147-S09851013102007101800000) .
6. Remove the radiator outlet hose from the radiator.

J 38185 Hose Clamp Pliers. See Special Tools .

J 38185 Hose Clamp Pliers. See Special Tools .

Scheme 31

Scheme 32

1. Drain the cooling system. Refer to «Draining and Filling Cooling System (LH6)»(ref-268147-S30426788732007101800000) or «Draining and Filling Cooling System (LL8)»(ref-268147-S34710564872007101800000) .
2. Using J 38185 reposition the radiator outlet hose clamp (3). See «Special Tools»(ref-268147-S09851013102007101800000) .
3. Remove the radiator outlet hose (2) from the radiator.
4. Using J 38185 reposition the radiator outlet hose clamp. See «Special Tools»(ref-268147-S09851013102007101800000) .
5. Remove the radiator outlet hose from the engine (5).
6. Remove the radiator outlet hose.

J 38185 Hose Clamp Pliers. See Special Tools .

Scheme 33

1. Drain the cooling system. Refer to «Draining and Filling Cooling System (LH6)»(ref-268147-S30426788732007101800000) or «Draining and Filling Cooling System (LL8)»(ref-268147-S34710564872007101800000) .
2. Using J 38185 reposition the radiator outlet hose clamp. See «Special Tools»(ref-268147-S09851013102007101800000) .
3. Remove the radiator outlet hose from the radiator.
4. Using J 38185 reposition the radiator outlet hose clamp. See «Special Tools»(ref-268147-S09851013102007101800000) .
5. Remove the radiator outlet hose from the engine (1).
6. Remove the radiator outlet hose.

J 46406 Fan Clutch Remover and Installer. See Special Tools .

Scheme 34

1. Drain the cooling system. Refer to «Draining and Filling Cooling System (LH6)»(ref-268147-S30426788732007101800000) or «Draining and Filling Cooling System (LL8)»(ref-268147-S34710564872007101800000) .
2. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(ref-268121-S41476428912007101800000) .
3. Remove the air resonator assembly. Refer to «Air Cleaner Outlet Resonator Replacement»(ref-268121-S20571828982007101800000) .
4. Remove the inlet radiator hose. Refer to «Radiator Inlet Hose Replacement (LH6)»(ref-268147-S38942730032007101800000) or «Radiator Inlet Hose Replacement (LL8)»(ref-268147-S29361189922007101800000) .
5. Remove the transmission oil cooler lines from the fan shroud.
6. Disconnect the fan clutch electrical connector.
7. Using J 46406 remove the fan clutch from the water pump. See «Special Tools»(ref-268147-S09851013102007101800000) .
8. Remove the mounting bolts from the upper fan shroud.
9. Lift and push the fan shroud inward to clear the filler neck on the radiator.
10. Remove the fan and the shroud.

J 43244 Relay Puller Pliers

Scheme 35

1. Remove the underhood electrical center cover.
2. Using the J 43244 , remove the cooling fan relay (3).

J 38185 Hose Clamp Pliers. See Special Tools .

Scheme 36

1. Remove the necessary coolant from the radiator. Refer to «Draining and Filling Cooling System (LH6)»(ref-268147-S30426788732007101800000) or «Draining and Filling Cooling System (LL8)»(ref-268147-S34710564872007101800000) .
2. Remove the generator. Refer to «Generator Replacement (4.2L Engine)»(ref-268108-S11577458102007101800000) or «Generator Replacement (5.3L Engine)»(ref-268108-S14779794212007101800000) .
3. Loosen the outlet hose clamp at the thermostat housing (1). Remove the outlet hose from the thermostat housing.
4. Remove the thermostat housing bolts.
5. Remove the thermostat housing from the engine block.
6. Clean all of the surfaces of the thermostat housing.
7. Clean the sealing surface of the engine block.

J 38185 Hose Clamp Pliers. See Special Tools .

Scheme 37

Scheme 38

Scheme 39

Scheme 40

1. Drain the cooling system. Refer to «Draining and Filling Cooling System (LH6)»(ref-268147-S30426788732007101800000) or «Draining and Filling Cooling System (LL8)»(ref-268147-S34710564872007101800000) .
2. Loosen the air cleaner outlet duct clamps at the following locations: Throttle body Mass air flow (MAF)/intake air temperature (IAT) sensor
3. Remove the air cleaner outlet duct bolt and duct.
4. Remove the accessory drive belt tensioner. Refer to «Drive Belt Tensioner Replacement - Accessory»(ref-268156-S09299672042007101800000) .
5. Remove the cooling fan and shroud. Refer to «Cooling Fan and Shroud Replacement»(ref-268147-S12673307262007101800000) .
6. Using the J 38185 , reposition the inlet hose clamp at the water pump. See «Special Tools»(ref-268147-S09851013102007101800000) .
7. Remove the inlet hose from the water pump.
8. Using the J 38185 , reposition the outlet hose clamp at the water pump. See «Special Tools»(ref-268147-S09851013102007101800000) .
9. Remove the outlet hose from the water pump.
10. Remove the auxiliary heater inlet and outlet hose/pipe nut.
11. Using the J 38185 , reposition the throttle body hose clamp at the throttle body. See «Special Tools»(ref-268147-S09851013102007101800000) .
12. Remove the hose from the throttle body.
13. Using the J 38185 , reposition the auxiliary heater inlet and outlet hose/pipe clamps at the water pump. See «Special Tools»(ref-268147-S09851013102007101800000) .
14. Remove the inlet and outlet hoses/pipes from the water pump.
15. Remove the water pump bolts.
16. Remove the water pump and gaskets.
17. Discard the water pump gaskets.

Scheme 41

1. Install the water pump and NEW gaskets. NOTE: Refer to «Fastener Notice»(ref-268087-S07010920292007101800000) . IMPORTANT: All gasket surfaces are to be free of oil or other foreign material during assembly.
2. Install the water pump bolts. Tighten: On the initial pass, tighten the bolts to 15 N.m (11 lb ft). On the final pass, tighten the bolts to 30 N.m (22 lb ft).
3. Install the auxiliary heater inlet and outlet hose/pipe nut. Tighten: Tighten the nut to 10 N.m (89 lb in).
4. Install the hose to the throttle body.
5. Using J 38185 , position the throttle body hose clamp at the throttle body. See «Special Tools»(ref-268147-S09851013102007101800000) .
6. Install the inlet and outlet hoses/pipes to the water pump.
7. Using J 38185 , position the auxiliary heater inlet and outlet hose/pipe clamps at the water pump. See «Special Tools»(ref-268147-S09851013102007101800000) .
8. Install the outlet hose to the water pump.
9. Using J 38185 , position the outlet hose clamp at the water pump. See «Special Tools»(ref-268147-S09851013102007101800000) .
10. Install the inlet hose to the water pump.
11. Using J 38185 , position the inlet hose clamp at the water pump. See «Special Tools»(ref-268147-S09851013102007101800000) .
12. Install the cooling fan and shroud. Refer to «Cooling Fan and Shroud Replacement»(ref-268147-S12673307262007101800000) .
13. Install the accessory drive belt tensioner. Refer to «Drive Belt Tensioner Replacement - Accessory»(ref-268156-S09299672042007101800000) .
14. Install the air cleaner outlet duct and bolt. Tighten: Tighten the bolt to 10 N.m (89 lb in).
15. Tighten the air cleaner outlet duct clamps at the following locations: Throttle body MAF/IAT sensor Tighten: Tighten the clamps to 7 N.m (62 lb in).
16. Fill the cooling system. Refer to «Draining and Filling Cooling System (LH6)»(ref-268147-S30426788732007101800000) or «Draining and Filling Cooling System (LL8)»(ref-268147-S34710564872007101800000) .

Tool Required

J 41240 Fan Clutch Remover and Installer. See Special Tools .

Scheme 42

Scheme 43

1. Drain the coolant. Refer to «Draining and Filling Cooling System (LH6)»(ref-268147-S30426788732007101800000) or «Draining and Filling Cooling System (LL8)»(ref-268147-S34710564872007101800000) .
2. Remove the fan and shroud. Refer to «Cooling Fan and Shroud Replacement»(ref-268147-S12673307262007101800000) .
3. Remove the drive belt. Refer to «Drive Belt Replacement»(ref-268132-S04886974512007101800000) .
4. Using the J 41240 , secure the water pump pulley and remove the water pump pulley bolts. See «Special Tools»(ref-268147-S09851013102007101800000) .
5. Remove the J 41240 . See «Special Tools»(ref-268147-S09851013102007101800000) .
6. Remove the water pump pulley.
7. Loosen and remove the water pump bolts.
8. Remove the water pump.
9. Clean and inspect the water pump. Refer to «Water Pump Cleaning and Inspection»(ref-268132-S40630321002007101800000) .
10. Discard and replace the gasket.

J 38185 Hose Clamp Pliers. See Special Tools .

Scheme 44

1. Drain the coolant from the radiator. Refer to «Draining and Filling Cooling System (LH6)»(ref-268147-S30426788732007101800000) or «Draining and Filling Cooling System (LL8)»(ref-268147-S34710564872007101800000) .
2. Recover the refrigerant. Refer to «Refrigerant Recovery and Recharging»(ref-268096-S34829348672007101800000) .
3. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-268088-S13434065972007101800000) .
4. Remove the lower radiator support shield, if equipped. Refer to «Radiator Support Shield Replacement»(ref-268103-S29603808222007101800000) .
5. Reposition the outlet radiator hose clamp using J 38185 . See «Special Tools»(ref-268147-S09851013102007101800000) .
6. Remove the outlet radiator hose (1) from the radiator.
7. Remove the transmission cooler lines from the radiator. Refer to «Transmission Fluid Cooler Hose/Pipe Quick-Connect Fitting Replacement»(ref-268097-S01015528202007101800000) .
8. Lower the vehicle.
9. Remove the cooling fan and shroud. Refer to «Cooling Fan and Shroud Replacement»(ref-268147-S12673307262007101800000) .
10. Remove the radiator support diagonal brace. Refer to «Radiator Support Diagonal Brace Replacement»(ref-268102-S15556797092007101800000) .
11. Remove the coolant recovery line from the radiator.
12. Disconnect the radiator side panels from the shroud (1).
13. Remove the radiator.
14. Remove the bolts retaining the condenser to the radiator.

Cooling Fan Control

The purpose of the electro-viscous (EV) fan clutch is to maintain powertrain cooling requirements. The powertrain control module (PCM) monitors the following sensors to regulate the fan speed

1. Engine coolant temperature sensor
2. A/C refrigerant pressure sensor
3. Vehicle speed sensor
4. Intake air temperature sensor
5. Transmission fluid temperature sensor
6. Ambient air temperature sensor

The PCM controls the electro-viscous fan clutch engagement. The PCM regulates a 12-volt pulse width modulated signal (PWM) to the cooling fan relay. The PWM signal determines the ON time of the relay. As the commanded state of the fan clutch increases, so does the ON time of the relay. This ON time directly effects the amount of time the solenoid, which is internal to the fan clutch, is energized. When the solenoid in the fan clutch is energized, it opens the spring loaded valve and allows fluid to flow from the storage chamber to the fluid coupling of the cooling fan clutch, increasing the fan speed. When the solenoid is de-energized, the spring loaded valve closes, and blocks the path of the fluid to the fluid coupling of the fan clutch, reducing fan speed.

The fan has the ability to create a feedback signal, so the PCM has an actual fan speed input. This is done with a hall effect sensor internal to the fan clutch. The PCM supplies a 5-volt reference and a low reference to the hall effect sensor. The hall effect sensor returns a signal pulse through the cooling fan speed signal circuit in response to the reluctor track passing by the magnetic field of the hall effect sensor.

The PCM commands the cooling fan to 100 percent under the following conditions

1. Engine coolant temperature exceeds approximately 129°C (264°F).
2. The transmission oil temperature exceeds approximately 151°C (304°F).
3. A/C refrigerant pressure exceeds 1655 kPa (240 psi).
4. When certain DTCs set-These include P0116, P0117, P0118, P0125, P1481, P1482, and P1484.

The scan tool can engage the cooling fan clutch. This is done with the engine controls special function menu screen. To engage the cooling fan, It can take up to 2 minutes for a 100 percent command with the engine at 2,000 RPM. The lower the engine speed, the longer it will take the fan to engage. To disengage the cooling fan, it can take up to 2 minutes with the engine at 2000 RPM. The lower the engine speed, the longer it will take to disengage. In lower ambient air temperatures the cooling fan will engage in less time, however, it will take longer to disengage due to the properties of the fluid vs. temperature.

Under certain conditions the cooling fan may be engaged at engine restart. They are as follows

1. The cooling fan was engaged at the time the engine was turned OFF.
2. The fluid may bleed from the storage chamber into the fluid coupling of the cooling fan.

Although the fan is commanded OFF at this time due to a cold start condition, this is the most likely time a vehicle driver will notice that the fan noise is excessive compared to normal engine starts with out cooling fan engaged. As the engine speed is increased the fan noise will be louder than before. These are normal conditions that can be very intermittent.

The purpose of the electro-viscous (EV) fan clutch is to maintain powertrain cooling requirements. The powertrain control module (PCM) monitors the following sensors to regulate the fan speed

1. Engine coolant temperature sensor
2. A/C refrigerant pressure sensor
3. Vehicle speed sensor
4. Intake air temperature sensor
5. Transmission fluid temperature sensor
6. Ambient air temperature sensor

The PCM controls the electro-viscous fan clutch engagement. The PCM regulates a 12-volt pulse width modulated signal (PWM) to the cooling fan relay. The PWM signal determines the ON time of the relay. As the commanded state of the fan clutch increases, so does the ON time of the relay. This ON time directly effects the amount of time the solenoid, which is internal to the fan clutch, is energized. When the solenoid in the fan clutch is energized, it opens the spring loaded valve and allows fluid to flow from the storage chamber to the fluid coupling of the cooling fan clutch, increasing the fan speed. When the solenoid is de-energized, the spring loaded valve closes, and blocks the path of the fluid to the fluid coupling of the fan clutch, reducing fan speed.

The fan has the ability to create a feedback signal, so the PCM has an actual fan speed input. This is done with a hall effect sensor internal to the fan clutch. The PCM supplies a 5-volt reference and a low reference to the hall effect sensor. The hall effect sensor returns a signal pulse through the cooling fan speed signal circuit in response to the reluctor track passing by the magnetic field of the hall effect sensor.

The PCM commands the cooling fan to 100% under the following conditions

1. Engine coolant temperature exceeds approximately 129°C (264°F).
2. The transmission oil temperature exceeds approximately 151°C (304°F).
3. A/C refrigerant pressure exceeds 1655 kPa (240 psi).
4. When certain DTC's set. These include P0116, P0117, P0118, P0125, P1481, P1482, and P1484.

The scan tool can engage the cooling fan clutch. This is done with the engine controls special function menu screen. To engage the cooling fan, It can take up to 2 minutes for a 100% command with the engine at 2000 RPM. The lower the engine speed, the longer it will take the fan to engage. To disengage the cooling fan, it can take up to 2 minutes with the engine at 2000 RPM. The lower the engine speed, the longer it will take to disengage. In lower ambient air temperatures the cooling fan will engage in less time, however, it will take longer to disengage due to the properties of the fluid vs. temperature.

Under certain conditions the cooling fan may be engaged at engine restart. They are as follows

1. The cooling fan was engaged at the time the engine was turned off
2. The fluid may bleed from the storage chamber into the fluid coupling of the cooling fan

Although the fan is commanded off at this time due to a cold start condition. This is the most likely time a vehicle driver will notice that the fan noise is excessive compared to normal engine starts with out cooling fan engaged. As the engine speed is increased the fan noise will be louder than before. These are normal conditions that can be very intermittent.

Engine Coolant Hot Idle Engine

The radio activates an audible warning as requested by the instrument panel cluster (IPC). The IPC sends a class 2 message to the radio indicating the chime duration of 4 pulses. The warning sounds and the appropriate indicator illuminates in the driver information center (DIC) when the following occurs

1. The IPC determines that the coolant temperature is greater than 125°C (257°F). The IPC receives a class 2 message from the PCM indicating coolant temperature.
2. The IPC performs the displays test at the start of each ignition cycle. The indicator illuminates for approximately 3 seconds.

The IPC turns OFF the engine coolant indicator when the engine coolant falls below 122°C (252°F).

Cooling System

The cooling system's function is to maintain an efficient engine operating temperature during all engine speeds and operating conditions. The cooling system is designed to remove approximately 1/3 of the heat produced by the burning of the air-fuel mixture. When the engine is cold, the coolant does not flow to the radiator until the thermostat opens. This allows the engine to warm quickly.

Cooling Cycle

Coolant is drawn from the radiator outlet and into the water pump inlet by the water pump. Coolant will then be pumped through the water pump outlet and into the engine block. In the engine block, the coolant circulates through the water jackets surrounding the cylinders, where the coolant absorbs heat.

Some coolant is also pumped from the water pump to the heater core, then back to the water pump. This provides the passenger compartment with heat and defrost.

The coolant is then forced through the cylinder head gasket openings and into the cylinder heads. In the cylinder heads, the coolant flows through the water jackets surrounding the combustion chambers and valve seats, where the coolant absorbs additional heat.

Coolant is also directed to the throttle body. There the coolant circulates through passages in the casting. During initial start up, the coolant assists in warming the throttle body. During normal operating temperatures, the coolant assists in keeping the throttle body cool.

From the cylinder heads, the coolant is then forced to the thermostat. The flow of coolant will either be stopped at the thermostat until the engine is warmed, or the coolant will flow through the thermostat and into the radiator where the coolant is cooled and the coolant cycle is completed.

Operation of the cooling system requires proper functioning of all cooling system components. The cooling system consists of the following components, which are described below

1. The coolant
2. The radiator
3. The pressure cap
4. The coolant recovery system
5. The air baffles and seals

Coolant

The engine coolant is a solution made up of a 50-50 mixture of DEX-COOL and suitable drinking water. The coolant solution carries excess heat away from the engine to the radiator, where the heat is dissipated to the atmosphere.

Radiator

The radiator is a heat exchanger, consisting of a core and 2 tanks. The aluminum core is a tube and fin crossflow design that extends from the inlet tank to the outlet tank. Fins are placed around the outside of the tubes to improve heat transfer to the atmosphere.

The inlet and outlet tanks are a molded, high temperature, nylon reinforced plastic material. A high temperature rubber gasket seals the tank flange edge to the aluminum core. The tanks are clamped to the core with clinch tabs. The tabs are part of the aluminum header at each end of the core.

The radiator also has a drain cock located in the bottom of the left hand tank. The drain cock unit includes the drain cock and drain cock seal.

The radiator removes heat from the coolant passing through the core. The fins on the core transfer heat from the coolant passing through the tubes. As air passes between the fins, the air removes the heat and cools the coolant.

Pressure Cap

The pressure cap seals the cooling system, and contains a blow-off or pressure valve, and a vacuum or atmospheric valve. The pressure valve is held against the seat by a spring, which protects the radiator from excess cooling system pressure. The vacuum valve is held against the seat by a spring, which permits the opening of the valve to relieve the vacuum created in the cooling system as the coolant cools off. The vacuum, if not relieved, might cause the radiator and/or coolant hoses to collapse.

The pressure cap allows cooling system pressure to build up as the temperature increases. As the pressure builds, the boiling point of the coolant increases. Engine coolant can be safely run at a temperature much higher than the boiling point of the coolant at atmospheric pressure. The hotter the coolant is, the faster the heat transfers from the radiator to the cooler, passing air.

The pressure in the cooling system can get too high. When the cooling system pressure exceeds the rating of the pressure cap, the pressure valve opens, venting the excess pressure.

As the engine cools down, the temperature of the coolant drops and a vacuum is created in the cooling system. This vacuum causes the vacuum valve to open, allowing outside air into the surge tank. This equalizes the pressure in the cooling system with atmospheric pressure, preventing the radiator and coolant hoses from collapsing.

Coolant Recovery System

The coolant recovery system consists of a plastic coolant recovery reservoir and overflow tube. The recovery reservoir is also called a recovery tank or expansion tank. This reservoir is partially filled with coolant and is connected to the radiator fill neck with the overflow tube. Coolant can flow back and forth between the radiator and the reservoir.

In effect, a cooling system with a coolant recovery reservoir is a closed system. When the pressure in the cooling system gets too high, the pressure valve opens in the pressure cap. This allows the coolant, which has expanded due to being heated, is allowed to flow through the overflow tube and into the recovery reservoir. As the engine cools down, the temperature of the coolant drops and a vacuum is created in the cooling system. This vacuum opens the vacuum valve in the pressure cap, allowing some of the coolant in the reservoir to be siphoned back into the radiator. Under normal operating conditions, coolant is not lost. Although the coolant level in the recovery reservoir goes up and down, the radiator and cooling system are kept full. An advantage to using a coolant recovery reservoir is that most of the air bubbles are eliminated from the cooling system. Coolant without bubbles absorbs heat much better than coolant with bubbles.

Air Baffles and Seals

The cooling system uses deflectors, air baffles and air seals to increase cooling system capability. Deflectors are installed under the vehicle to redirect airflow beneath the vehicle and through the radiator to increase engine cooling. Air baffles are also used to direct airflow through the radiator and increase cooling capability. Air seals prevent air from bypassing the radiator and A/C condenser, and prevent recirculation of hot air for better hot weather cooling and A/C condenser performance.

Water Pump

The water pump is a centrifugal vane impeller type pump. The pump consists of a housing with coolant inlet and outlet passages and an impeller. The impeller is mounted on the pump shaft and consists of a series of flat or curved blades or vanes on a flat plate. When the impeller rotates, the coolant between the vanes is thrown outward by centrifugal force.

The impeller shaft is supported by one or more sealed bearings. The sealed bearings never need to be lubricated. Grease cannot leak out, dirt and water cannot get in as long as the seal is not damaged or worn.

The purpose of the water pump is to circulate coolant throughout the cooling system. The water pump is driven by the crankshaft via the drive belt.

Thermostat

The thermostat is a coolant flow control component. Its purpose is to help regulate the operating temperature of the engine. It utilizes a temperature sensitive wax-pellet element. The element connects to a valve through a small piston. When the element is heated, it expands and exerts pressure against the small piston. This pressure forces the valve to open. As the element is cooled, it contracts. This contraction allows a spring to push the valve closed.

When the coolant temperature is below the rated thermostat opening temperature, the thermostat valve remains closed. This prevents circulation of the coolant to the radiator and allows the engine to warm up. After the coolant temperature reaches the rated thermostat opening temperature, the thermostat valve will open. The coolant is then allowed to circulate through the thermostat to the radiator where the engine heat is dissipated to the atmosphere. The thermostat also provides a restriction in the cooling system, after it has opened. This restriction creates a pressure difference which prevents cavitation at the water pump and forces coolant to circulate through the engine block.

Transmission Oil Cooler

The transmission oil cooler is a heat exchanger. It is located inside the right side end tank of the radiator. The transmission fluid temperature is regulated by the temperature of the engine coolant in the radiator.

The transmission oil pump, pumps the fluid through the transmission oil cooler line to the transmission oil cooler. The fluid then flows through the cooler where the engine coolant absorbs heat from the fluid. The fluid is then pumped through the transmission oil cooler return line, to the transmission.

Coolant Heater

The optional engine coolant heater (RPO K05) is rated at 400 watts and supplies 1365 btu/hr. The engine coolant heater operates using 110 volt AC external power and is designed to warm the coolant in the engine block area for improved starting in very cold weather -29°C (-20°F). The coolant heater helps reduce fuel consumption when a cold engine is warming up. The unit is equipped with a detachable AC power cord. A weather shield on the cord is provided to protect the plug when not in use.