Coolant: Testing and Inspection
INSPECTION1. RELATIONSHIP OF SUBARU COOLANT CONCENTRATION AND FREEZING TEMPERATURE
The concentration and safe operating temperature of the SUBARU coolant is shown in the diagram. Measuring the temperature and specific gravity of the coolant will provide this information.
[Example]
If the coolant temperature is 25°C (77°F) and its specific gravity is 1.054, the concentration is 35% (point A), the safe operating temperature is -14°C (7°F) (point B), and the freezing temperature is -20°C (-4°F) (point C).
2. PROCEDURE TO ADJUST THE CONCENTRATION OF THE COOLANT
To adjust the concentration of the coolant according to temperature, find the proper fluid concentration in the above diagram and replace the necessary amount of coolant with an undiluted solution of SUBARU genuine coolant (concentration 50%).
The amount of coolant that should be replaced can be determined using the diagram.
[Example]
Assume that the coolant concentration must be increased from 25% to 40%. Find point A, where the 25% line of coolant concentration intersects with the 40% curve of the necessary coolant concentration, and read the scale on the vertical axis of the graph at height A. The quantity of coolant to be drained is 2.1 liters (2.2 US qt, 1.8 Imp qt). Drain 2.1 liters (2.2 US qt, 1.8 Imp qt) of coolant from the cooling system and add 2.1 liters (2.2 US qt, 1.8 Imp qt) of the undiluted solution of SUBARU coolant.
If a coolant concentration of 50% is needed, drain all the coolant and refill with the undiluted solution only.
INSPECTION
1. Check radiator for leakage, filling it with coolant and attach radiator cap tester (A) to the filler neck. Then apply a pressure of 157 kPa (1.6 kg/sq.cm, 23 psi) and check the following points:
- Each portion of radiator for leakage
- Hose joints and other connections for leakage
CAUTION: When attaching or detaching tester and when operating tester, use special care not to deform radiator filler neck.
NOTE:
- When performing this check, be sure to keep the engine stationary and fill radiator with coolant.
- Wipe off check points before applying pressure.
- Use care not to spill coolant when detaching tester from radiator.
2. Check the radiator cap valve open pressure using radiator cap tester.
CAUTION: Rust or dirt on cap may prevent valve from functioning normally: be sure to clean cap before testing.
- Raise the pressure until the needle of gauge stops and see if the pressure can be retained for five to six seconds. The radiator cap is normal if a pressure above the service limit value has been maintained for this period.
Radiator cap valve open pressure
Standard value:
93-128 kPa (0.95 - 1.25 kg/sq.cm, 14 - 18 psi)
Service limit:
83 kPa (0.85 kg/sq.cm, 12 psi)
3. If the coolant temperature exceeds 76.0 to 80.0°C (169 to 176°F) while radiator is not so hot, check thermostat. If thermostat does not open at 76.0 to 80.0°C (169 to 176°F), replace it with a new one.
4. If electric fan does not operate when coolant temperature exceeds 90 to 94°C (194 to 201°F), check thermoswitch or fan motor.
To prevent cooling system leaks, always add Genuine Subaru cooling system Conditioner (Part No. SOA635071) whenever the coolant is replaced.
The content of this article/image reflects the changes called out by TSB - 18-74-04-mu.