COVER AS-VALVE MECHANISM 1503138 - Caterpillar

Climbing equipment may be required to access this service point. Refer to the Operation and Maintenance Manual, "Mounting and Dismounting"
topic for safety information.
Overfilling the overflow tank (if equipped) will result in damage to the cooling system.If the cooling system has an overflow tank, maintain the coolant level in the tank below 1/2 full in order to avoid damage to the cooling system.
Observe the coolant level in the sight gauge (if equipped). When the engine is running at normal operating temperature, the coolant should be in the upper half of the sight gauge. If the coolant level is low, add the proper coolant mixture.Add Coolant
Note: For the proper coolant mixture to use, see this Operation and Maintenance Manual, "Fluid Recommendations" topic and this Operation and Maintenance Manual, "Refill Capacities" topic.
Stop the engine. Allow the engine to cool.
Remove the cooling system filler cap slowly in order to relieve any pressure. Pour the proper coolant mixture into the filler pipe.
Illustration 1 g00103639
Filler cap gaskets
Clean the cooling system filler cap. Inspect the gaskets of the cooling system filler cap. If the gaskets are damaged, replace the old cooling system filler cap with a new cooling system filler cap. Install the cooling system filler cap.
Start the engine. Inspect the cooling system for leaks.