VALVE GP-RELIEF 2244530 - 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 [below 5°C (40°F)].Radiator Restrictions
Caterpillar discourages the use of air flow restriction devices mounted in front of radiators. Air flow restriction can cause higher exhaust temperatures, power loss, excessive fan usage, and a reduction in fuel economy.If an air flow restriction device must be used, the device should have a permanent opening directly in line with the fan hub. The device must have a minimum opening dimension of at least 770 cm2 (120 in2).A centered opening, directly in line with the fan hub, is specified to provide sensing when viscous fan drives are used and/or to prevent an interrupted air flow on the fan blades. Interrupted air flow on the fan blades could cause a fan failure.Air temperature in the inlet manifold should not exceed 65°C (150°F). Temperatures exceeding this limit can cause power loss and potential engine damage. Caterpillar recommends an inlet manifold temperature device, such as a light indicator, buzzer, etc., set at 65°C (150°F) and/or installation of an inlet air temperature gauge.This temperature provides engine protection for full restriction device closure. This temperature can also serve as a diagnostic tool for a malfunction of the charge air cooling system. It is not anticipated that a temperature of 65°C (150°F) will be encountered under normal operating conditions.Fuel and the Effect from Cold Weather
The two types of diesel fuel available for your engine are typically grades No.1 and No.2. No.2 diesel fuel is the most commonly used fuel. No.1 diesel fuel, or a blend of No.1 and No.2, is best suited for cold weather operation.Quantities of No.1 diesel fuel are limited, and generally only available during the winter months in the colder climates. During cold weather operation, if No.1 fuel is unavailable, it may be necessary to use No.2 diesel fuel.There are three major differences between No.1 and No.2 diesel fuel. No.1 diesel fuel has:* a lower cloud point* a lower pour point* a lower BTU (kJ) (heat content) rating per unit volume of fuel than the average No.2 diesel fuelWhen using No.1 diesel fuel, you may notice a drop in power and fuel efficiency. You should not experience any other operating effects.The cloud point is the temperature at which a cloud or haze of wax crystals begins to form in the fuel and cause fuel filters to plug. The pour point is the temperature which diesel fuel begins to thicken and be more resistant to flow through fuel pumps and lines.Be aware of these fuel values when purchasing your diesel fuel. 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