HARNESS ASSEMBLY-WIRING 4P9537 - Caterpillar

Caterpillar Diesel Engines can operate effectively in cold weather, however, engine operation in cold weather is dependent on the type of fuel used and how well the fuel moves through fuel related components. The purpose of this section is to explain some of the problems and steps that can be taken to minimize fuel problems during cold weather operation when the engine area is colder than 5°C (40°F).Fuel Effects from Cold Weather
The two types of diesel fuel available for your engine are typically grades No. 1 and No. 2. Although No. 2 diesel fuel is the most commonly used fuel, No. 1 diesel fuel is the fuel that is best suited for cold weather operation.During cold weather operation, it may be necessary for you to use No. 2 diesel fuel since quantities of No. 1 diesel fuel are limited and generally are only available during the winter months and in the colder climates.There are two major differences between No. 1 and No. 2 diesel fuel. No. 1 diesel fuel has a lower cloud point and a lower pour point.The cloud point is the temperature at which a cloud or haze of wax crystals will begin to form in the fuel and cause fuel filters to plug. Fuel waxing can plug fuel filters in cold weather and significantly reduce or stop the fuel flow to the engine.The fuel cloud point must be below the temperature of the surrounding (ambient) air to prevent filter waxing and power loss. The pour point is the temperature which diesel fuel will begin to thicken and be more resistant to flow through fuel pumps and lines.Be aware of these fuel values when purchasing your diesel fuel and anticipate the average outside (ambient) temperature for the area your engine will be operating. Engines fueled in one climate may not operate satisfactorily if moved to another because of problems that result from cold weather. The average No. 1 diesel fuel has a lower kJ (BTU) (heat content) rating per unit volume of fuel than the average No. 2 diesel fuel. When using No. 1 diesel fuel, you may notice a drop in power and fuel efficiency, but should not experience any other operating effects.Before troubleshooting for low power or poor performance in winter months, check the type of fuel being used.Fuel heating attachments are available from your Caterpillar dealer to minimize these problems.The use of starting aids, engine oil pan heaters, engine coolant heaters, fuel heaters and fuel line insulation also provide a means of minimizing starting and fuel problems in cold weather when No. 2 diesel fuel is used.Fuel Related Components in Cold Weather
Fuel Heaters
Fuel heaters prevent plugging of the fuel filters in cold weather due to waxing. Non-thermostatically controlled fuel heaters can heat the fuel in excess of 65°C (150°F). High fuel temperatures reduce engine performance and reliability.A fuel heater should be installed so that the fuel is heated before it enters the first (primary) fuel filter.Use a fuel heater that is mechanically simple,