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Engine Cooling System (Except Wrx): Diagnosis Subaru XV GP

Cooling System (Mechanical) 18 illustrations ~1442 words

DIAGNOSIS

Radiator main fan and radiator sub fans do not rotate under the above operating conditions.

StepCheckYesNo
1 CHECK OPERATION OF RADIATOR FAN. Connect the delivery (test) mode connector. Turn the ignition switch to ON. Perform the compulsory operation check for the radiator fan relay using Subaru Select Monitor. NOTE: When performing a forced operation radiator fan relay check using the Subaru Select Monitor, the radiator main fan and radiator sub fan will repeat low speed revolution --> high speed revolution --> OFF in this order. Subaru Select Monitor For detailed operation procedures, refer to "PC application help for Subaru Select Monitor".Do the radiator main fans and radiator sub fans rotate at low speed?Go to step 2 .Go to step 3 .
2 CHECK OPERATION OF RADIATOR FAN. Connect the delivery (test) mode connector. Turn the ignition switch to ON. Perform the compulsory operation check for the radiator fan relay using Subaru Select Monitor. NOTE: When performing a forced operation radiator fan relay check using the Subaru Select Monitor, the radiator main fan and radiator sub fan will repeat low speed revolution --> high speed revolution --> OFF in this order. Subaru Select Monitor For detailed operation procedures, refer to "PC application help for Subaru Select Monitor".Do the radiator main fans and radiator sub fans rotate at high speed?Radiator main fan system is normal.Go to step 27 .
3 CHECK POWER SUPPLY TO SUB FAN RELAY. Turn the ignition switch to OFF. Remove the sub fan relay from the relay holder. Measure the voltage between the sub fan relay terminal and chassis ground. Connector & terminal (F27) No. 17 (+) - Chassis ground (-)Is the voltage 10 V or more?Go to step 4 .Go to step 5 .
4 CHECK POWER SUPPLY TO SUB FAN RELAY. Turn the ignition switch to ON. Measure the voltage between the sub fan relay terminal and chassis ground. Connector & terminal (F27) No. 20 (+) - Chassis ground (-)Is the voltage 10 V or more?Go to step 7 .Go to step 6 .
5 CHECK FUSE. Turn the ignition switch to OFF. Remove the fuse No. 3. Check the condition of fuse.Is the fuse blown out?Replace the fuse.Repair the power supply line.
6 CHECK FUSE. Turn the ignition switch to OFF. Remove the fuse No. 22. Check the condition of fuse.Is the fuse blown out?Replace the fuse.Repair the power supply line.
7 CHECK SUB FAN RELAY. Turn the ignition switch to OFF. Measure the resistance between sub fan relay terminals. Terminals No. 17 - No. 18Is the resistance 1 Mohms or more?Go to step 8 .Replace the sub fan relay. < Refer to RELAY AND FUSE . >
8 CHECK SUB FAN RELAY. Connect the battery to terminals No. 13 and No. 12 of the sub fan relay. Measure the resistance between sub fan relay terminals. Terminals No. 17 - No. 18Is the resistance less than 1 ohms?Go to step 9 .Replace the sub fan relay. < Refer to RELAY AND FUSE . >
9 CHECK HARNESS BETWEEN SUB FAN RELAY TERMINAL AND SUB FAN MOTOR CONNECTOR. Disconnect the connector from the sub fan motor. Measure the resistance of harness between the sub fan relay terminal and sub fan motor connector. Connector & terminal (F16) No. 1 - (F27) No. 18Is the resistance less than 1 ohms?Go to step 10 .Repair the open circuit of harness between sub fan relay terminal and sub fan motor connector.
10 CHECK HARNESS BETWEEN SUB FAN MOTOR CONNECTOR AND MAIN FAN RELAY 2 CONNECTOR. Remove main fan relay 2 from the relay holder. Measure the resistance of harness between sub fan motor connector and main fan relay 2 connector. Connector & terminal (F16) No. 2 - (F27) No. 12Is the resistance less than 1 ohms?Go to step 11 .Repair the open circuit of the harness between sub fan motor connector and main fan relay 2 connector.
11 CHECK FOR POOR CONTACT. Check poor contact of sub fan motor connector.Is there poor contact of the sub fan motor connector?Repair the poor contact of sub fan motor connector.Go to step 12 .
12 CHECK SUB FAN MOTOR. Connect the battery positive (+) terminal to terminal No. 2 of the sub fan motor, and the ground (-) terminal to terminal No. 1.Does the radiator sub fan rotate?Go to step 13 .Replace the sub fan motor. < Refer to RADIATOR SUB FAN AND FAN MOTOR . >
13 CHECK MAIN FAN RELAY 2. Measure the resistance of main fan relay 2. Terminals No. 14 - No. 12Is the resistance less than 1 ohms?Go to step 14 .Replace the main fan relay 2. < Refer to RELAY AND FUSE . >
14 CHECK HARNESS BETWEEN MAIN FAN RELAY 2 AND MAIN FAN MOTOR CONNECTOR. Disconnect the connector from the main fan motor. Measure the resistance of the harness between main fan relay 2 terminal and main fan motor connector. Connector & terminal (F17) No. 1 - (F27) No. 14Is the resistance less than 1 ohms?Go to step 15 .Repair the open circuit of the harness between main fan relay 2 terminal and main fan motor connector.
15 CHECK GROUND CIRCUIT OF MAIN FAN MOTOR. Measure the resistance between main fan motor connector and chassis ground. Connector & terminal (F17) No. 2 - Chassis groundIs the resistance less than 5 ohms?Go to step 16 .Repair the open circuit of the harness between main fan motor connector and chassis ground.
16 CHECK FOR POOR CONTACT. Check poor contact of main fan motor connector.Is there poor contact of the main fan motor connector?Repair the poor contact of main fan motor connector.Go to step 17 .
17 CHECK MAIN FAN MOTOR. Connect the battery positive (+) terminal to terminal No. 2 of the main fan motor, and the ground (-) terminal to terminal No. 1.Does the radiator main fan rotate?Go to step 18 .Replace the main fan motor. < Refer to RADIATOR MAIN FAN AND FAN MOTOR . >
18 CHECK HARNESS BETWEEN SUB FAN RELAY AND ECM. Disconnect the connector from ECM. Measure the resistance between the sub fan relay terminal and ECM connector. Connector & terminal (B135) No. 11 - (F27) No. 19Is the resistance less than 1 ohms?Go to step 19 .Repair the open circuit of harness between sub fan relay terminal and ECM.
19 CHECK FOR POOR CONTACT. Check for poor contact of ECM connector.Is there poor contact of ECM connector?Repair the poor contact of ECM connector.Check the DTC. Repair the trouble cause. < Refer to READ DIAGNOSTIC TROUBLE CODE (DTC) . >
20 CHECK MAIN FAN RELAY 1. Turn the ignition switch to OFF. Remove main fan relay 1 from the main fuse box. Measure the resistance between terminals of main fan relay 1 switch.Is the resistance 1 Mohms or more?Go to step 21 .Replace the main fan relay 1. < Refer to RELAY AND FUSE . >
21 CHECK MAIN FAN RELAY 1. Connect the main fan relay 1 coil side terminal to the battery. Measure the resistance between terminals of main fan relay 1 switch.Is the resistance less than 1 ohms?Go to step 22 .Replace the main fan relay 1. < Refer to RELAY AND FUSE . >
22 CHECK HARNESS BETWEEN MAIN FAN RELAY 1 AND MAIN FAN MOTOR CONNECTOR. Disconnect the connector from the main fan motor. Measure the resistance of the harness between main fan relay 1 terminal and main fan motor connector. Connector & terminal (F17) No. 1 - (F36) No. 6Is the resistance less than 1 ohms?Go to step 23 .Repair the open circuit of the harness between main fan relay 1 terminal and main fan motor connector.
23 CHECK HARNESS BETWEEN MAIN FAN RELAY 1 AND ECM. Disconnect the connector from ECM. Measure the resistance between main fan relay 1 terminal and ECM connector. Connector & terminal (B135) No. 12 - (B143) No. 15Is the resistance less than 1 ohms?Go to step 24 .Repair the open circuit of the harness between main fan relay 1 terminal and ECM.
24 CHECK HARNESS BETWEEN MAIN FAN RELAY 2 AND ECM. Measure the resistance between main fan relay 2 terminal and ECM connector. Connector & terminal (B135) No. 12 - (F27) No. 15Is the resistance less than 1 ohms?Go to step 25 .Repair the open circuit of the harness between main fan relay 2 terminal and ECM.
25 CHECK FUSE. Turn the ignition switch to OFF. Remove the fuse No. 2 and No. 26. Check the condition of fuse.Is the fuse blown out?Replace the fuse.Go to step 26 .
26 CHECK FOR POOR CONTACT. Check for poor contact of ECM connector.Is there poor contact of ECM connector?Repair the poor contact of ECM connector.Repair the power supply circuit to the main fuse box.
27 CHECK OPERATION OF RADIATOR FAN. If the both fans do not rotate at high speed in the condition of step 2, check whether the radiator sub fan is rotating.Does the radiator sub fan rotate?Go to step 20 .Go to step 28 .
28 CHECK GROUND CIRCUIT OF MAIN FAN RELAY 2. Remove the main fan relay 2 from A/C relay holder. Measure the resistance between main fan relay 2 terminal and chassis ground. Connector & terminal (F27) No. 13 - Chassis groundIs the resistance less than 1 ohms?Go to step 29 .Repair the open circuit of harness between main fan relay 2 and chassis ground.
29 CHECK POWER SUPPLY TO MAIN FAN RELAY 2. Turn the ignition switch to ON. Measure the voltage between main fan relay 2 terminal and chassis ground. Connector & terminal (F27) No. 16 (+) - Chassis ground (-)Is the voltage 10 V or more?Go to step 30 .Repair the power supply line.
30 CHECK MAIN FAN RELAY 2. Turn the ignition switch to OFF. Remove the main fan relay 2. Measure the resistance of main fan relay 2. Terminals (F27) No. 12 - (F27) No. 13Is the resistance 1 Mohms or more?Go to step 31 .Replace the main fan relay 2. < Refer to RELAY AND FUSE . >
31 CHECK MAIN FAN RELAY 2. Connect the battery to terminals No. 20 and No. 22 of the main fan relay 2. Measure the resistance of main fan relay 2. Terminals (F27) No. 12 - (F27) No. 13Is the resistance less than 1 ohms?Go to step 23 .Replace the main fan relay 2. < Refer to RELAY AND FUSE . >
NOTE
When performing a forced operation radiator fan relay check using the Subaru Select Monitor, the radiator main fan and radiator sub fan will repeat low speed revolution --> high speed revolution --> OFF in this order. Subaru Select Monitor For detailed operation procedures, refer to "PC application help for Subaru Select Monitor".
NOTE
When performing a forced operation radiator fan relay check using the Subaru Select Monitor, the radiator main fan and radiator sub fan will repeat low speed revolution --> high speed revolution --> OFF in this order. Subaru Select Monitor For detailed operation procedures, refer to "PC application help for Subaru Select Monitor".

INSPECTION

Note. When adding the engine coolant, always use SUBARU Super Coolant.

  1. Park the vehicle on a level surface.
  2. Check the engine coolant amount, and if the coolant level is low, check for the coolant leakage, and then add the engine coolant. Make sure the engine coolant level in the reservoir tank is between "FULL" and "LOW" with the engine in a cold condition. Open the radiator cap and make sure that the radiator is filled with the engine coolant up to its filler neck position.

Scheme 6

Scheme 6: DRAINING OF ENGINE COOLANT
Scheme 6: DRAINING OF ENGINE COOLANT
  1. Lift up the vehicle.
  2. Remove the under cover. < Refer to «REMOVAL»(ref-560372-S42274069342013061300000) , Front Under Cover. >
  3. Remove the drain plug to drain engine coolant into container. NOTE: Remove the radiator cap so that engine coolant will drain faster.
  4. Install the drain plug.
  5. Install the under cover. < Refer to «INSTALLATION»(ref-560372-S19308806142013061300000) , Front Under Cover. >

Scheme 7

Scheme 7: FILLING OF ENGINE COOLANT
Scheme 7: FILLING OF ENGINE COOLANT
  1. Pour cooling system conditioner through the filler neck. Cooling system protective agent: Refer to "SPECIFICATION" for cooling system protective agent. < Refer to «SPECIFICATION»(ref-560359-S41529218832013061300000) , Cooling System Protective Agent, General Description. >
  2. Pour engine coolant into the radiator up to the filler neck position. Recommended engine coolant: Refer to "SPECIFICATION" for recommended engine coolant. < Refer to «SPECIFICATION»(ref-560359-S41529218832013061300000) , Engine Coolant, General Description. > Engine coolant level: Refer to "SPECIFICATION" for engine coolant level. < Refer to «SPECIFICATION»(ref-560359-S41529218832013061300000) , Engine Coolant, General Description. > Engine coolant concentration: Refer to "ADJUSTMENT" for the recommended engine coolant concentration. < Refer to «ADJUSTMENT»(ref-560359-S09096298332013061300000) , Engine Coolant. > NOTE: The SUBARU Super Coolant contains anti-freeze and anti-rust agents, and is especially made for Subaru engines with an aluminum cylinder block. Be sure to use SUBARU Super Coolant, since other coolant may cause corrosion.
  3. Fill engine coolant into the reservoir tank up to "FULL" level.
  4. Close the radiator cap and start the engine. Race 5 to 6 times at 3, 000 rpm or less, then stop the engine. (Complete this operation within 40 seconds.)
  5. Wait for one minute after the engine stops, and open the radiator cap. If the engine coolant level drops, add engine coolant into radiator up to the filler neck position.
  6. Perform the procedures 4) and 5) again.
  7. Attach the radiator cap and reservoir tank cap properly.
  8. Start the engine and operate the heater at maximum hot position and the blower speed setting to "LO".
  9. Run the engine at 2, 000 rpm or less until radiator fan starts and stops. NOTE: Be careful with the engine coolant temperature to prevent overheating.
  10. Stop the engine and wait until the engine coolant temperature lowers to 30°C (86°F) or less.
  11. Open the radiator cap. If the engine coolant level drops, add engine coolant into the radiator up to the filler neck position and the reservoir tank to "FULL" level.
  12. Attach the radiator cap correctly.
  13. Set the heater setting to maximum hot position and the blower speed setting to "LO" and start the engine. Perform racing at 3, 000 rpm or less. If the flowing sound is heard from heater core at this time, perform the procedures from 9) again.
  1. Check the water pump bearing for smooth rotation.
  2. Check the water pump pulley for abnormalities.
  3. Make sure the impeller is not abnormally deformed or damaged.

Scheme 8

Scheme 8
Scheme 8

Scheme 9

Scheme 9
Scheme 9
  1. Disconnect the ground cable from battery.
  2. Lift up the vehicle.
  3. Remove the under cover. < Refer to «REMOVAL»(ref-560372-S42274069342013061300000) , Front Under Cover. >
  4. Drain engine coolant. < Refer to «DRAINING OF ENGINE COOLANT»(ref-560359-S12749968242013061300000) , REPLACEMENT, Engine Coolant. >
  5. Remove the front exhaust pipe. < Refer to «REMOVAL»(ref-560376-S32386970822013061300000) , Front Exhaust Pipe. >
  6. Disconnect the radiator outlet hose from thermostat cover.
  7. Remove the thermostat cover, and then remove the gasket and thermostat.

Scheme 10

Scheme 10
Scheme 10

Scheme 11

Scheme 11
Scheme 11

Scheme 12

Scheme 12
Scheme 12

Scheme 13

Scheme 13
Scheme 13

Scheme 14

Scheme 14
Scheme 14

Scheme 15

Scheme 15
Scheme 15

Scheme 16

Scheme 16
Scheme 16

Scheme 17

Scheme 17
Scheme 17
  1. Lift up the vehicle.
  2. Remove the under cover. < Refer to «REMOVAL»(ref-560372-S42274069342013061300000) , Front Under Cover. >
  3. Drain engine coolant. < Refer to «DRAINING OF ENGINE COOLANT»(ref-560359-S12749968242013061300000) , REPLACEMENT, Engine Coolant. >
  4. Lower the vehicle.
  5. Disconnect the ground cable from battery.
  6. Remove the clip (A) from the air intake boot.
  7. Loosen the clamp (B) connecting the air intake boot and air cleaner case (rear).
  8. Loosen the clamp (C) which connects the air intake boot and throttle body.
  9. Remove the air intake boot from the throttle body, and move the air intake boot to the left side wheel apron.
  10. Disconnect the engine harness connector. Remove the bolt securing the bulkhead harness connector bracket. Disconnect the bulkhead harness connector from the engine harness connector (black) and engine harness connector (brown).
  11. Disconnect the connector (A) from manifold absolute pressure sensor.
  12. Disconnect the connector (B) from the throttle position sensor.
  13. Disconnect the connector (C) from the EGR control valve.
  14. Remove the bolt securing the engine hanger from the cylinder block RH, and move the hanger to the right side wheel apron.
  15. Disconnect the hose from the thermostat cover.
  16. Remove the thermostat cover, and then remove the thermostat and gasket.

Scheme 18

Scheme 18: ENGINE SIDE
Scheme 18: ENGINE SIDE
  1. Install a gasket to thermostat. NOTE: Use a new gasket.
  2. Install the thermostat and thermostat cover. Tightening torque: 6.4 N.m (0.7 kgf-m, 4.7 ft-lb)
  3. Connect the radiator outlet hose to thermostat cover.
  4. Install the front exhaust pipe. < Refer to «INSTALLATION»(ref-560376-S08119204982013061300000) , Front Exhaust Pipe. >
  5. Install the under cover. < Refer to «INSTALLATION»(ref-560372-S19308806142013061300000) , Front Under Cover. >
  6. Lower the vehicle.
  7. Connect the battery ground terminal.
  8. Fill engine coolant. < Refer to «FILLING OF ENGINE COOLANT»(ref-560359-S08077404332013061300000) , REPLACEMENT, Engine Coolant. >

Scheme 19

Scheme 19: ATF COOLER (WITH WARMER FEATURE) SIDE
Scheme 19: ATF COOLER (WITH WARMER FEATURE) SIDE
  1. Install a gasket to thermostat. NOTE: Use a new gasket.
  2. Install the thermostat and thermostat cover. NOTE: Install the parts with the air vent hole facing upward. Tightening torque: 6.4 N.m (0.7 kgf-m, 4.7 ft-lb)
  3. Connect the hose to the thermostat cover.
  4. Install the engine hanger to the cylinder block RH. Tightening torque: 21 N.m (2.1 kgf-m, 15.5 ft-lb)
  5. Connect the connector (A) to the manifold absolute pressure sensor.
  6. Connect the connector (B) to the throttle position sensor.
  7. Connect the connector (C) to the EGR control valve.
  8. Connect the engine harness connector. Connect the bulkhead harness connector to the engine harness connector (black) and engine harness connector (brown). Install the bolt which secures the bulkhead harness connector bracket. Tightening torque: 7.5 N.m (0.8 kgf-m, 5.5 ft-lb)
  9. Install the air intake boot. < Refer to «INSTALLATION»(ref-560358-S35284385082013061300000) , Air Intake Boot. >
  10. Connect the battery ground terminal.
  11. Lift up the vehicle.
  12. Install the under cover. < Refer to «INSTALLATION»(ref-560372-S19308806142013061300000) , Front Under Cover. >
  13. Lower the vehicle.
  14. Fill engine coolant. < Refer to «FILLING OF ENGINE COOLANT»(ref-560359-S08077404332013061300000) , REPLACEMENT, Engine Coolant. >
  1. Check that the thermostat does not have deformation, cracks or damage.
  2. Check that the thermostat valve closes completely at an ambient temperature.
  3. Immerse the thermostat and a thermometer in water. Raise water temperature gradually, and check the temperature and valve lift when the valve begins to open and when the valve is fully opened. Replace the thermostat if faulty.

Note. During the test, agitate the water for even temperature distribution. Leave the thermostat in the boiling water for five minutes or more before measuring the valve lift. Hold the thermostat with a wire or the like to avoid contacting with container bottom.

Starting temperature to open

Engine side

87 - 91°C (189 - 196°F)

ATF cooler (with warmer feature) side

48 - 52°C (118 - 126°F)

Full open temperature

Engine side

98°C (208°F)

ATF cooler (with warmer feature) side

63°C (145°F)

Total valve lift

Engine side

8.0 mm (0.315 in) or more

ATF cooler (with warmer feature) side

6.0 mm (0.236 in) or more

Scheme 20

Scheme 20
Scheme 20

Check that the radiator main fan, radiator main fan shroud and main fan motor assembly do not have deformation, cracks or damage.

Scheme 21

Scheme 21
Scheme 21

Scheme 22

Scheme 22
Scheme 22
  1. Disconnect the ground cable from battery.
  2. Remove the air intake duct. < Refer to «REMOVAL»(ref-560358-S09391633272013061300000) , Air Intake Duct. >
  3. Disconnect the connector from the sub fan motor assembly.
  4. Remove the bolts which hold the radiator sub fan shroud onto the radiator.
  5. Remove the radiator sub fan and fan motor from vehicle.

Check that the radiator sub fan, radiator sub fan shroud and sub fan motor assembly do not have deformation, cracks or damage.

Scheme 23

Scheme 23: REMOVAL
Scheme 23: REMOVAL
  1. Disconnect the over flow hose (A) connected to the radiator filler neck from the reservoir tank.
  2. Pull out the reservoir tank to the arrow direction while pushing the claw (B).
  1. Check that the reservoir tank does not have deformation, cracks or damage.
  2. Make sure the over flow hoses are not cracked, damaged or loose.
  3. Make sure the engine coolant level is between "FULL" and "LOW".
TroublePossible causeCorrective action
Over-heatingA. Insufficient engine coolantReplenish engine coolant, inspect for leakage, and repair it if necessary.
B. Defective thermostatReplace.
C. Malfunction of water pumpReplace.
D. Clogged engine coolant passageClean.
E. Improper ignition timingInspect and repair ignition control system. < Refer to BASIC DIAGNOSTIC PROCEDURE . >
F. Clogged or leaking radiatorClean, repair or replace.
G. Defective radiator capReplace.
H. Improper engine oil in engine coolantReplace the engine coolant. If ineffective, check, repair or replace engine components.
I. Air/fuel mixture ratio too leanInspect and repair the fuel injection system. < Refer to BASIC DIAGNOSTIC PROCEDURE . >
J. Excessive back pressure in exhaust systemClean or replace.
K. Insufficient clearance between piston and cylinderAdjust or replace.
L. Slipping clutchRepair or replace.
M. Dragging brakeAdjust.
N. Malfunction of radiator fanInspect the radiator fan relay, engine coolant temperature sensor or fan motor and replace them.
Over-coolingA. Ambient temperature extremely lowPartly cover radiator front area.
B. Defective thermostatReplace.
Engine coolant leaksA. Loosened or damaged connecting units on hosesRepair or replace.
B. Leakage from water pumpReplace.
C. Leakage from water pipeRepair or replace.
D. Leakage around cylinder head gasketRetighten cylinder head bolts or replace cylinder head gasket.
E. Damaged or cracked cylinder head and cylinder blockRepair or replace.
F. Damaged or cracked thermostat coverRepair or replace.
G. Leakage from radiatorRepair or replace.
NoiseA. Defective radiator fanReplace.
B. Defective water pump bearingReplace water pump.
C. Defective water pump mechanical sealReplace water pump.

More articles — Engine Cooling System (Except Wrx)