994K Wheel Loader Caterpillar

Selection of the Oil Change Interval

The standard hydraulic oil change interval for this machine is at every 2000 Service Hours or 1 Year. By performing S·O·S oil analysis, the hydraulic oil change interval may be extended up to 4000 Service Hours or 2 Years. S·O·S oil analysis must be performed at every 500 Service Hours or 3 Months in order to extend the hydraulic oil change interval. The results from the S·O·S oil analysis will determine if the hydraulic oil change interval may be extended. If S·O·S oil analysis is not available, the hydraulic oil change interval must remain at every 2000 Service Hours or 1 Year. Refer to the Operation and Maintenance Manual, "S·O·S Information".

Reference: Refer to Operation and Maintenance Manual, "Lubricant Viscosities" for a list of recommended oils to use in the hydraulic system of this machine.

The use of Cat HYDO Advanced 10 allows for a 50% increase in the standard oil change interval for machine hydraulic systems. The standard hydraulic oil change interval for this machine when using Cat HYDO Advanced 10 is at every 3000 Service Hours or 18 Months. By performing S·O·S oil analysis, the hydraulic oil change interval may be extended up to 6000 Service Hours or 3 Years. S·O·S oil analysis must be performed at every 500 Service Hours or 3 Months in order to extend the hydraulic oil change interval. The results from the S·O·S oil analysis will determine if the hydraulic oil change interval may be extended. If S·O·S oil analysis is not available, the hydraulic oil change interval when using Cat HYDO Advanced 10 must remain at every 3000 Service Hours or 18 Months. Refer to the Operation and Maintenance Manual, "S·O·S Information".

Note: Follow the service interval for hydraulic system oil filter changes that is listed in the Maintenance Interval Schedule in the Operation and Maintenance Manual for any hydraulic oil change interval that is used.

Special Procedures

Special procedures may be required in the event of a catastrophic failure in the implement and hydraulic fan hydraulic system.

These special procedures may include, but not limited to, the following:

• Disassembly of the hydraulic oil tank for cleaning debris from the tank

• Removal of strainers from the hydraulic oil tank for cleaning debris

• Checking magnetic plugs in pump case drain manifolds for debris

• Cleaning or replacing hydraulic system high-pressure screens

Reference: For more information about checking the magnetic plugs in pump case drain manifolds, refer to Operation and Maintenance Manual, "Magnetic Plug - Check, Implement and Hydraulic Fan Hydraulic System".

Reference: For more information about cleaning or replacing hydraulic system high-pressure screens, refer to Operation and Maintenance Manual, "High Pressure Screens - Clean/Replace, Implement and Hydraulic Fan Hydraulic System".

Procedure for Changing the Hydraulic Oil

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Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin.

Note: Be sure that you obtain an S·O·S hydraulic oil sample before you drain the hydraulic oil.

1. Operate the machine in order to warm the oil.

2. Park the machine on level ground. Lower the work tool to the ground with a slight downward pressure. Engage the parking brake and stop the engine.
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   Illustration 1	g03844611
   Platform access door open to reveal top of hydraulic oil (implement/hydraulic fan) tank (1) Filler cap (2) Breaker relief valve (3) Access door

3. Open platform access door (3) that is to the right of the right-hand ROPS post. Press the button on top of breaker relief valve (2) to relieve any hydraulic oil tank pressure.

4. Remove hydraulic oil tank filler cap (2). Remove the strainer from the filler tube.

5. Wash the strainer and the filler cap in a clean, nonflammable solvent. Dry these components thoroughly. Install the strainer in the filler tube.
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   Illustration 2	g03829242
   Service center in rear bumper on left-hand side of machine (4) Fast fill service panel (5) Service center access door

6. Open access door (5) to the service center that is located on the left-hand side of the rear bumper. The fast fill port and the ecology drain for the implement and hydraulic fan hydraulic system are located in fast fill service panel (4).

   Reference: For more information about using the hydraulic system oil (implement/hydraulic fan) ecology drain and fast fill port, refer to Operation and Maintenance Manual, "Service Center, Fast Fill Service Panel".

7. Position a suitable container beneath the fast fill service panel. Remove the drain plug from the appropriate ecology drain.

8. Install an adapter into the ecology drain housing in order to unseat the drain valve. Allow the oil to drain into a suitable container.

   Note: A 4C-8563 Swivel or a 25.4 mm (1 inch) pipe with 1-11 1/2 NPTF threads may be used to unseat the drain valve.

9. When the hydraulic oil is finished draining from the hydraulic oil tank, remove the adapter that was installed in step 8.

10. Clean the drain plug and install the drain plug.

11. Fill the hydraulic oil tank with clean oil by using the filler tube on top of the hydraulic oil tank.

    Note: The hydraulic oil tank fast fill port in the fast fill service panel can also be utilized to refill the hydraulic oil tank. This method of filling the hydraulic oil tank is described at the end of this section.

    Reference: Refer to Operation and Maintenance Manual, "Lubricant Viscosities and Refill Capacities" for the type of lubricant and for the refill capacity.

12. Inspect the gasket on the hydraulic tank filler cap for damage. Replace the gasket, if necessary. Install the filler cap.
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    Illustration 3	g03590480
    (6) Hydraulic oil level gauge

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    Illustration 4	g02937798
    Enlarged view of hydraulic oil level gauge (6). Arrows indicate the normal operating level of hydraulic oil visible in the hydraulic oil level gauge.

13. Hydraulic oil level gauge (6) for the implement and hydraulic fan hydraulic oil system is located on the front surface of the hydraulic system oil tank. The hydraulic oil level gauge can be seen beneath the right-hand platform near the articulation joint. Maintain the hydraulic oil level within the designated range shown by the arrows in illustration 4.

14. Start the engine and run the engine for at least 10 seconds. Then, stop the engine and add hydraulic oil to the hydraulic oil tank if necessary. Maintain the oil level within the normal operating level of the hydraulic oil level gauge.

15. Start the engine and run the engine at low idle. Cycle the implements so that all hydraulic systems are filled with oil.

16. Stop the engine and top off the hydraulic oil tank if necessary. Maintain the oil level within the normal operating level of the hydraulic oil level gauge.

    Note: The oil must be free of air bubbles. If air bubbles are present in the hydraulic oil, air is entering the hydraulic system. Inspect the hydraulic suction line and the hose clamps.

17. If necessary, tighten any loose clamps or any loose connections. Replace any damaged hoses.

18. Stop the engine. Close the access door.

Fast Fill Port

Hydraulic oil may be added to the hydraulic oil tank through hydraulic oil tank (implement/hydraulic fan) fast fill port that is located in the service center.

1. Remove the dust cover from the hydraulic oil tank fast fill port.

2. Attach the hose to the male coupling. Use a 127-9088 Nozzle for this port.

3. Add the oil, as needed.

4. When finished adding oil, replace the dust cover to the hydraulic oil tank fast fill port.

Reference: For more information about using the hydraulic system oil (implement/hydraulic fan) ecology drain and fast fill port, refer to Operation and Maintenance Manual, "Service Center, Fast Fill Service Panel".