EDGE GP-CUTTING 1359385 - Caterpillar

November 7, 1984 Truck Engine News, Page 4, "New Water Temperature Regulator Has Higher Temperature Setting ".The Reference Article announced that the opening temperature of the 4W4842 Regulator used in 3406B and 3408B Truck Engines was increased from 82 °C (180°F) to 88°C (190°F). A higher opening temperature provides a slight increase in fuel economy and better cold weather operation. Field reports indicate some drivers do not know about this increase in opening temperature.
The purpose of any water temperature regulator is to control minimum jacket coolant temperature (engine operating temperature). An engine temperature regulator in proper working condition DOES NOT AFFECT MAXIMUM ENGINE OPERATING TEMPERATURE. Once the temperature regulator is fully opened, the engine operating temperature is determined by other factors, the major ones being ambient temperature, engine load, and cooling system condition and design.
Dash-mounted temperature gauges provide only an approximate temperature of the engine jacket coolant. The temperature must be verified with a more accurate gauge if engine overheating is suspected.