Forester F4-2.5L (2008)
Coolant: Testing and Inspection
INSPECTION
RELATIONSHIP OF ENGINE COOLANT CONCENTRATION AND FREEZING TEMPERATURE
The concentration and safe operating temperature of engine coolant is shown in Diagram 1. 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).
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Diagram 1
PROCEDURE TO ADJUST THE CONCENTRATION OF THE ENGINE COOLANT
To adjust the concentration of engine coolant according to temperatures, find the proper fluid concentration in Diagram 1 and replace the necessary
amount of coolant with an undiluted solution of engine coolant (concentration 50%).
The amount of engine coolant that should be replaced can be determined using Diagram 2.
[Example]
Assume that the engine coolant concentration must be increased from 25% to 40%. Find point A, where the 25% line of engine coolant concentration
intersects with the 40% curve of the necessary engine coolant concentration, and read the scale on the vertical axis of the graph at height A. In this
case, the amount of engine coolant to be drained is 2.1 l (2.2 US qt, 1.8 Imp qt). Drain 2.1 l (2.2 US qt, 1.8 Imp qt) of engine coolant from the cooling
system and add 2.1 l (2.2 US qt, 1.8 Imp qt) of the undiluted solution of engine coolant.
If a coolant concentration of 50% is needed, drain all the coolant and refill with the undiluted solution only.
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Diagram 2