Engine Cooling System (H4SO) (Except Sti): Diagnosis Subaru Impreza GH

DIAGNOSIS

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

DIAGNOSIS PROCEDURE CHART

Scheme 47

1. Set the vehicle on a lift.
2. Lift up the vehicle.
3. Remove the under cover RH.
4. Remove the drain plug (A) to drain engine coolant into container. NOTE: Remove the radiator cap so that engine coolant will drain faster.
5. Install the drain plug.
6. Install the under cover RH.

Scheme 48

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-357238-S36779050342010031100000) , 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-357238-S36779050342010031100000) , General Description . Engine coolant level: Refer to "SPECIFICATION" for engine coolant level. Refer to «SPECIFICATION»(ref-357238-S36779050342010031100000) , General Description . Engine coolant concentration: Refer to «ADJUSTMENT»(ref-357238-S03092781452010031100000) for the recommended engine coolant concentration., 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. Always 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 gauge to prevent overheating.
10. Stop the engine and wait until the engine coolant temperature drops 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.

INSPECTION

Replace the thermostat if the valve does not close completely at an ambient temperature or if the following test shows unsatisfactory results.

1. Inspection method

Immerse the thermostat and a thermometer in water. Raise water temperature gradually, and measure the temperature and valve lift when the valve begins to open and when the valve is fully opened. During the test, agitate the water for even temperature distribution. The measured value should meet the specification.

Note. Leave the thermostat in the boiling water for five minutes or more before measuring valve lift. Hold the thermostat with a wire or the like to avoid contacting the container.

Starting temperature to open

80 - 84°C (176 - 183°F)

Full open temperature

95°C (203°F)

Total valve lift

9.0 mm (0.354 in) or more

Scheme 49

Make sure the engine coolant level is between "FULL" and "LOW".

ENGINE COOLING SYSTEM TROUBLE REFERENCE