HEAD 2633391 - Caterpillar

Do not work in a position that is in line with the broken component. Coolant pushed out of the cylinder through the orifice in the component has tremendous force. The stream of coolant can severely injure a serviceman if it strikes him. To reduce the possibility of injury, the serviceman must use the procedure which follows.
1. Drain the coolant from the engine.2. Remove the broken or damaged component and the fuel nozzle. If part of the broken component remains in the cylinder head, remove the part before any other steps are done.3. Turn the crankshaft by hand through one complete revolution to remove any coolant from the cylinder.4. If necessary, the crankshaft can now be turned by the starter.