105921-4165 ZEXEL 9 420 612 175 BOSCH GOVERNOR 9420612175 1059214165 223005033a

Always Allow the Engine to Reach Normal Operating Temperature
Damage to valves and components during operation in very cold temperature conditions can result from engine operation for short intervals. Damage to the engine can occur from starting the engine and stopping the engine many times without allowing the engine to reach normal operating temperature. The fuel and the oil are not completely burned in the combustion chambers while the engine is operating below the normal operating temperature. This fuel and oil causes soft carbon deposits on the valve stems. Generally, these deposits do not cause problems because these deposits are burned off during operation at normal engine temperatures. When the engine is started and the engine is stopped frequently the engine may not reach the normal operating temperature. This will cause the carbon deposits to become thicker. This will prevent the free operation of the valves. This can also cause the following conditions: valves to stick, pushrods to bend and other damage to valve train components. Begin operating the engine at low load. After the engine oil pressure is normal and the coolant temperature begins to rise, the engine may be operated at full load. Allow the engine to reach normal operating temperature. This will keep the carbon deposits on the valve stems at a minimum. This will also maintain free operation of the valves and the valve train components. The engine will remain in better condition and the service life of the engine may be extended when the engine is warmed up properly. Lubrication will be improved, with less acid and sludge in the oil. This will give longer service life for the engine bearings, the piston rings, and other parts. However, limit unnecessary idle time to ten minutes. Engine wear is greatest at low idle and unnecessary idling wastes fuel. Engine Block Heaters
A block heater can improve the startability and a block heater can reduce the warm up time by heating the coolant that surrounds the combustion chambers. An electric block heater can be activated immediately after the engine is stopped. The use of a block heater will reduce the temperature that would require a starting aid. An effective block heater is typically a 1250/1500 W unit. Contact your truck dealer for more information.On/Off Fan Clutch
For better control of the operation of the fan, an ON/OFF fan clutch may be used. ON/OFF fan clutches can help prevent excessive cooling in cold weather. Often, a viscous fan drive will rotate continuously in cold weather. Fan clutches that keep the fan stationary in the OFF position reduce unnecessary movement of air in order to help maintain adequate engine operating temperatures. For some engines, if a viscous fan drive must be specified, select a "slow speed" viscous fan drive that turns the fan at 200 to 250 rpm at engine idle speed. Contact your OEM dealer for more information. Bypass Valves and Insulated Heater Lines
The coolant must be able to bypass the radiator in order