REGULATOR AS 4604135 - Caterpillar

Engines With a Coolant Recovery Tank
Note: The cooling system may not have been provided by Caterpillar. The procedure that follows is for typical cooling systems. Refer to the OEM information for the correct procedures.Check the coolant level when the engine is stopped and cool.
Observe the coolant level in the coolant recovery tank. Maintain the coolant level to "COLD FULL" mark on the coolant recovery tank.
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.
Loosen filler cap slowly in order to relieve any pressure. Remove the filler cap.
Pour the correct coolant mixture into the tank. Refer to the Operation and Maintenance Manual, "Refill Capacities and Recommendations" for information on the correct mixture and type of coolant. Refer to the Operation and Maintenance Manual, "Refill Capacities and Recommendations" for the cooling system capacity. Do not fill the coolant recovery tank above "COLD FULL" mark.
Illustration 1 g03781633
(1) Gaskets
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 recovery tank during engine operation. When the engine is stopped and cool, the coolant will return to the engine.Engines Without a Coolant Recovery Tank
Check the coolant level when the engine is stopped and cool.
Illustration 2 g00285520
Cooling system filler cap
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.
Remove the cooling system filler cap slowly in order to relieve pressure.
Maintain the coolant level within 13 mm (0.5 inch) of the bottom of the filler pipe. If the engine is equipped with a sight glass, maintain the coolant level to the correct level in the sight glass.
Clean the cooling system filler cap and inspect the gasket. If the gasket is damaged, discard the old filler cap and install a new filler cap. If the gasket is not damaged, use a suitable pressurizing pump in order to pressure test the filler cap. The correct pressure is stamped on the face of the filler cap. If the filler cap does not retain the correct pressure, install a new filler cap.
Inspect the cooling system for leaks.