Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2021 Subaru Forester BaseFACTORY OEM SERVICE PROCEDURE
Engine Cooling System: General Description: Specification
| Cooling system | Electric fan + Forced engine coolant circulation system | ||||
|---|---|---|---|---|---|
| Total engine coolant capacity | L (US qt, Imp qt) | Approx. 8.5 (9.0, 7.5) | |||
| Water pump | Type | Centrifugal impeller type | |||
| Pump characteristics | Discharge rate | L (US gal, Imp gal)/min | 256 (67.6, 56.3) or more | ||
| Engine coolant temperature | °C (°F) | 80 (176) | |||
| Engine coolant concentration | % | 50 | |||
| System pressure | kPa (mAq) | 88 (9.0) | |||
| Pump speed | r/min | 8, 580 | |||
| Impeller diameter | mm (in) | 56 (2.20) | |||
| Number of impeller vanes | pcs. | 7 | |||
| Pump pulley effective diameter | mm (in) | 100 (3.94) | |||
| Thermo control valve assembly | Flow rate characteristics | Position 1 | Radiator port | 20.9 kPa (2.1 mAq) @ 100 L (26.4 US gal, 22.0 Imp gal)/min |
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| Position 2 | Bottom port | 41.6 kPa (4.2 mAq) @ 100 L (26.4 US gal, 22.0 Imp gal)/min |
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| Position 3 (fully closed) | - | - | |||
| Position 4 | Bottom port | 15.7 kPa (1.6 mAq) @ 30 L (7.9 US gal, 6.6 Imp gal)/min | |||
| Heater port | 28.5 kPa (2.9 mAq) @ 20 L (5.3 US gal, 4.4 Imp gal)/min | ||||
| Position 5 | Radiator port | 9.7 kPa (1.0 mAq) @ 100 L (26.4 US gal, 22.0 Imp gal)/min | |||
| Heater port | 12.0 kPa (1.2 mAq) @ 20 L (5.3 US gal, 4.4 Imp gal)/min | ||||
| Responsiveness | Fully closed - Fully open | sec | 2 or less | ||
| Sensor output range | V | 0.539 - 4.141 (mechanical stop position: 4.297) | |||
| Rotor operation range | deg | 174 | |||
| Failsafe thermostat | Type | Temperature, pressure relief | |||
| Starting temperature to open | °C (°F) | 105 - 109 (221 - 228) | |||
| Starting pressure to open | kPa (mAq) | 210 - 290 (21.4 - 29.6) | |||
| Thermostat | Type | Water tank pipe side | Wax pellet type | ||
| Starting temperature to open | °C (°F) | Water tank pipe side | 63 - 67 (145 - 153) | ||
| Full open temperature | °C (°F) | Water tank pipe side | 80 (176) | ||
| Valve lift | mm (in) | Water tank pipe side | 5.5 (0.217) or more | ||
| Valve opening size | mm (in) | Water tank pipe side | 22 (0.87) | ||
| Radiator fan | Motor input | W | Main fan | 120 | |
| Sub fan | 120 | ||||
| Fan outer diameter | mm (in) | Main fan | 320 (12.6) | ||
| Sub fan | 320 (12.6) | ||||
| Number of fan blades | pcs. | Main fan | 9 | ||
| Sub fan | 11 | ||||
| Radiator | Type | Down flow, pressure type | |||
| Core dimensions | mm (in) | Width x Height x Thickness | 687.4 x 390 x 16 (27.06 x 15.35 x 0.63) | ||
| Pressure range in which cap valve is open | (kg/cm2 , psi) | Positive pressure side | Standard | 93 - 123 (0.95 - 1.25, 14 - 18) | |
| Limit | 83 (0.85, 12) | ||||
| Negative pressure side | Standard | -1.0 - -4.9 or less (-0.01 - -0.05, -0.1 - -0.7) |
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| Fin shape | Corrugated fin | ||||
| Reservoir tank | Capacity | L (US qt, Imp qt) | 0.45 (0.476, 0.396) | ||
Engine coolant:
Refer to "RECOMMENDED MATERIALS" for engine coolant. Ref. to RECOMMENDED MATERIALS .
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.