Usage:
D379, D398, D399 Industrial and Marine Engines
Reference: (Because of the type of information in this article, it is not written in Caterpillar Fundamental English.)
Description of Change: National and international regulations require that some unattended engines have some type of protection from fuel line breakage. Double-walled fuel lines were developed to meet these requirements and have been approved by each marine classifications society. The double-walled fuel injection lines are available as attachments for D379, D398 and D399 Industrial and Marine Engines.
Double-walled fuel injection lines consist of two steel fuel lines, one inside the other. Adequate clearance between the inner and outer lines allows fuel from a possible ruptured inner line to flow through the outer line to a drain area. At the drain area, drain lines are connected to a drain tank. An outlet on the drain tank can be connected to a larger reservoir at the time of installation. A plug at the fitting for the drain line is used to identify which fuel injection line has ruptured. Also, the drain tank is equipped with a float switch which can be used to activate an alarm as the drain tank fills.
All of the fuel line fittings were designed with extra sealing ability and have the capacity to drain back so leakage will be sent into the outer fuel line. The double-walled fuel lines are routed the same as standard fuel injection lines. In this way, special mounting or relocation of other attachments is not required.
Double-walled fuel injection lines groups and the corresponding drain groups are not available for parts service as groups. But, the separate parts of each group can be ordered for the respective engine models as shown in the following chart:
INSTALLATION: Use the Service Manuals for D379, D398 and D399 to remove the standard fuel injection lines. Install the double-walled fuel injection lines and the fuel drain groups as shown in the Parts Books for D379, D398 and D399.
NOTE: Use the correct size crowfoot wrench to assemble the fuel lines. Tighten the fuel line fittings to a torque of 30 ± 5 lb ft (40 ± 7 N·m).