SEAL-O-RING 4911544 - Caterpillar

At operating temperature, the engine coolant is hot and under pressure. Steam can cause personal injury. Check the coolant level only after the engine has been stopped and the fill cap is cool enough to touch with your bare hand. Remove the fill cap slowly to relieve pressure. Cooling system conditioner contains alkali. Avoid contact with skin and eyes to prevent personal injury.
1. Release the pressure in the cooling system. Drain the coolant from the radiator. The capacity of the cooling system is 44 liters (11.4 U.S. gal). 2. Loosen the two hose clamps, and slide hose (1) up and off of pipe (2).3. Remove the four bolts and the washers that hold pipe (2) to the top of the cylinder head assembly. Remove pipe (2).
Typical Example4. Remove water temperature regulator (3) and the gasket from the cylinder head assembly. The following steps are for the installation of the water temperature regulator.
If the water temperature regulator is installed wrong, it will cause the engine to overheat.
5. Put water temperature regulator (3) and the gasket in position on the cylinder head assembly.6. Put pipe (2) in position on the cylinder head, with the plug toward the front of the engine. Install the four bolts that hold it.7. Position hose (1) on pipe (2), and tighten the two hose clamps.8. Fill the cooling system with coolant to the correct level. See the Operation & Maintenance Manual for the correct filling procedure.