General Information
The engine produces large quantities of heat during its operation. Too high or low an engine operating temperature will damage the engine. The purpose of the cooling system is to keep the engine at its optimum operating temperature. The optimum operating temperature results in the most efficient use of fuel and allows the engine oil to do its job properly.
The cooling system on Western Star vehicles is a closed or pressure type system, with a mixture of antifreeze and water. By pressurizing the system and using an antifreeze/water mixture, the boiling temperature of the coolant is raised, permitting more efficient, higher operating temperatures.
The coolant supplied with a Western Star vehicle is a 50/50 mix of antifreeze and water giving protection down to –35°F (–37°C). It is recommended that this be the minimum antifreeze mixture strength used. The maximum coolant mixture of 60 percent antifreeze to 40 percent water gives freeze protection to –62°F (–52°C).
Over-concentration of antifreeze or coolant conditioner can cause silicate to settle out of the coolant, forming a silica-gel on cooling system inner surfaces, resulting in overheating.
In addition, the tendency for silica-gel to form increases with water hardness. Hard water (with high levels of calcium and magnesium ions) increases likelihood of the formation of silica-gel. Do not use softened water. The salt used to artificially soften it is corrosive. Most engine manufacturers prefer use of distilled or de-ionized water to reduce the potential and severity of silica dropouts.
Keep the cooling system filled. On vehicles equipped with a frontwall-mounted translucent surge tank (see Fig.), keep the coolant level between the FULL and LOW marks. On vehicles equipped with a frontwall-mounted steel surge tank (see Fig.), keep the cooling system filled so that coolant can be seen in the sight glass in the surge tank. On vehicles equipped with a radiator-mounted translucent surge tank (see Fig.), keep the coolant level between the FULL and LOW marks. If the coolant is low, add the antifreeze solution mixture specified for the vehicle in PartsPro (Group 01).
-
Surge Tank
-
Fill Cap
Fig. 1, Frontwall-Mounted Translucent Surge Tank
-
Steel Surge Tank
-
SAE Pressure/Filler Cap
-
Sight Glass
-
Low Coolant Sensor
Fig. 2, Steel Surge Tank, High Flow Radiators
-
Surge Tank Pressure Relief Cap
-
Surge Tank Filler Cap
-
Cold Maximum Coolant Level
-
Cold Minimum Coolant Level
-
Coolant Level Sensor