FILTER-AIR 5220794 - Caterpillar

Personal injury can result from escaping fluid under pressure.If a pressure indication is shown on the indicator, push the release valve in order to relieve pressure before removing any hose from the heat exchanger.
Remove the water temperature regulator from the engine.
Heat water in a pan until the temperature is 97 °C (207 °F). Stir the water in the pan. This allows the temperature to radiate throughout the pan.
Hang the water temperature regulator in the pan of water. The water temperature regulator must be below the surface of the water. The water temperature regulator must be away from the sides and the bottom of the pan.
Keep the water at the correct temperature for ten minutes.
After ten minutes, remove the water temperature regulator. The water temperature regulator should have opened. Perform an immediate check of the distance for the openings on the water temperature regulator.Refer to the Specifications, "Water Temperature Regulator" for more information about the minimum distance for openings on the water temperature regulator. If the distance is less than the amount listed in the manual, replace the water temperature regulator.