SEAL AS-BUFFER 1672202 - Caterpillar

Check the coolant level when the engine is stopped and cool.
Pressurized System: Hot coolant can cause serious burns. To open the cooling system filler cap, stop the engine and wait until the cooling system components are cool. Loosen the cooling system pressure cap slowly in order to relieve the pressure.
Illustration 1 g03871129
Typical header tank
Loosen filler cap slowly in order to relieve any pressure. Remove the filler cap.
Pour the proper coolant mixture into the tank until the coolant reaches the baffle (1). Refer to this Operation and Maintenance Manual, "Coolant - Change" for additional information in filling the cooling system. Refer to the Operation and Maintenance Manual, "Fluid Recommendations" for information on the correct mixture and type of coolant. Refer to the Operation and Maintenance Manual, "Refill Capacities" for the cooling system capacity.
Clean filler cap and the receptacle. Reinstall the filler cap and inspect the cooling system for leaks. Note: The coolant will expand as the coolant heats up during normal engine operation. The additional volume will be forced into the coolant tank during engine operation. When the engine is stopped and cool, the coolant will return to the engine.