259D Skid Steer Loaders Machine Systems – Gear Motor (Fan) – Test

------ WARNING! ------

Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine.

To prevent possible injury, perform the procedure that follows before testing and adjusting the power train.



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.


Table 1
236D, 242D, 257D, 259D.     1200 ± 50 RPM     2850 ± 50 RPM    
246D, 262D, 277D, 279D, 287D, 289D.     1200 ± 50 RPM     2450 ± 50 RPM    
272D, 297D, 299D.     1200 ± 50 RPM     2600 ± 50 RPM    


This test is performed in order to ensure that the gear motor (fan) is running at the proper speed.

Required Tools

Table 2
Tool     Part Number     Part Description    
A     275-5120     Communication Adapter Gp    
B     9U-7400     Multitach Tool Gp    
C     1U-6605     Reflective Tape    

Test Preparation

Before any tests are performed, prepare the machine. Refer to Testing and Adjusting, "Machine Preparation". Before any tests are performed, visually inspect the complete hydraulic system for oil leaks and damaged parts. Refer to Testing and Adjusting, "Visual Inspection".

Note: The oil in the hydraulic system must be at an operating temperature of 50° ± 10°C (122° ± 180°F). This temperature range is specified for standard factory fill oil only. Use the Electronic Technician Software in order to monitor this temperature. Or refer to Testing and Adjusting, "Hydraulic Oil Temperature Test" for an alternate procedure.

  1. Release the hydraulic system pressure. Refer to Testing and Adjusting, "Hydraulic System Pressure - Release" for the correct procedure.

Test Procedure

    Illustration 1g01364212

    (1) Diagnostic connection

  1. Install Tooling (A) to the diagnostic connector (1) of the machine in order to measure engine rpm.

  1. Connect Tooling (A) and the Caterpillar Electronic Technician (ET).

  1. Open the engine access door.

    Illustration 2g01364215

    (B) Tooling

  1. Install Tooling (B) in order to measure fan rpm. Use the reflective tape (C) that is on the fan blade.

  1. Set the throttle to the HIGH IDLE position.

    Illustration 3g01372106

    (D) "Diagnostic" drop-down menu

    (E) "Diagnostic Tests"

    (F) "Override Parameters"

  1. Use the ET software in order to change the maximum fan current override value to 0%. Refer to Illustration 3 for the "Diagnostic" screen display. Click on "Override Paramaters".

  1. Record the maximum fan speed value.

  1. Use the ET software in order to change the maximum fan current override value to 100%.

  1. Record the minimum fan speed value.

  1. If the fan speed is not within the specification, use the Electronic Technician in order to perform the fan speed calibration procedure. Refer to Table 1 for the specification.

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