3608 Engine Caterpillar

Replace the secondary fuel filter elements when either of the following conditions occurs:

• The fuel filter differential pressure reaches 105 kPa (15 psi).

• The elements have been used for a maximum of 1500 hours of operation.

Filter Operation

The filter may be operated with the fuel flow through one side of the filter or through both sides of the filter. Either practice is acceptable, provided that the maximum fuel filter differential pressure is not exceeded. Operating with the fuel flow through one side of the filter is recommended.

Operating With One Side of the Filter

Caterpillar recommends operating with the fuel flow through one side of the filter during normal operation. This practice enables the filter elements to be replaced without shutting down the engine. When the maximum fuel filter differential pressure is reached, redirect the fuel flow through the new filter element. The dirty element may then be replaced during operation. The new replacement element is ready for use when the next element is replaced.

Operating With Both Sides of the Filter

When both sides of the filter are active, each element filters 50 percent of the fuel flow. This increases the time between replacement of the elements. However, this practice may require the engine to be shut down in order to replace the elements. This may be suitable for intermittent operation, but not for continuous operation.

During operation, the fuel flow must be directed through one side of the filter in order to replace an element. To avoid exceeding the maximum fuel filter differential pressure during operation, the element must be replaced before the element has reached the maximum pressure. To achieve optimum use of the filter elements, direct the fuel flow through one side of the filter.

Replacing the Filter Element During Engine Operation

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Filter contains hot pressurized fluid when engine is running. Follow instructions on control valve to avoid personal injury. If rapid air movement exists to blow fluid, Stop the engine to avoid fire.

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Illustration 1	g00655941
(1) Lever (2) Plug (3) Lever (3) Drain (4) Nut

1. Move lever (1) to the parallel position in order to allow the fuel to flow between the filters.
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   NOTICE
   Do not allow dirt to enter the fuel system. Thoroughly clean the area around a fuel system component that will be disconnected. Fit a suitable cover over disconnected fuel system component.

2. Slowly loosen vent plug (2) on the dry filter.
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   NOTICE
   Use a suitable container to catch any fuel that might spill. Clean up any spilled fuel immediately.

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   NOTICE
   Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products. Dispose of all fluids according to local regulations and mandates.

3. When the fuel flows without bubbles from the vent, the pressure in both of the filters is equalized. Tighten vent plug (2). Clean up any fuel that has spilled.

4. Move lever (3) in order to direct the fuel flow away from the side of the filter that will be serviced.

5. Loosen vent plug (2) of the filter that is being serviced. Do not remove the plug.
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   NOTICE
   To prevent contamination of the new filter element, ensure that the filter housing is completely drained.

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   NOTICE
   Keep all parts clean from contaminants. Contaminants may cause rapid wear and shortened component life.

6. Remove drain plugs (4) of the filter that is being serviced. Drain the fuel into a suitable container.
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   Illustration 2	g00715641
   (5) Nut (6) O-ring seal (7) Nut (8) Element

7. Remove nuts (5) and the cover . Be careful not to damage O-ring seal (6).

8. Remove nuts (7) and the retainer.

9. Remove six elements (8). Discard the used elements.

10. Clean the following items with clean, nonflammable solvent:

    • Inside of the filter housing

    • Components inside the filter housing

    • Retainer

    • Cover

    • Seal

    • Drain plugs

    Wipe the items dry with a clean cloth. Ensure that the surfaces for the seal are clean.

11. Install six new filter elements. Secure the element with the retainer and nuts (7). Install drain plugs (4).

12. Inspect O-ring seal (6) for good condition.

    Obtain a new seal, if necessary.

13. Install seal (6) in the cover. To make installation easier, coat the seal with clean diesel fuel. Install the cover. Secure the cover with nuts (5).

14. Tighten vent plug (2).

Replacing the Filter Elements With the Engine Stopped

1. Ensure that the fuel to the filter is OFF.

2. Refer to "Replacing the Filter Element During Engine Operation". Perform Steps 5 through 14 for both sides of the fuel filter.

3. Turn ON the fuel to the filter.

4. Turn handle (3) in order to fill the housings. Observe the area around vent plugs (2) for fuel flow. When fuel flows free of air bubbles, tighten the vent plugs. Clean up any fuel that has spilled.