Modification To Cooling System Prevents Hydraulic Oil System Overheating In Very Cold Operating Environments Caterpillar

Modification To Cooling System Prevents Hydraulic Oil System Overheating In Very Cold Operating Environments

Usage:

WHEEL LOADERS980G (2KR1-Up, 9CM1-Up, 2SR1-Up) WHEEL LOADERS

Problem:

In very cold ambient temperature conditions (typically less than -18 C° (0 F°) ), the cooling system may "overcool" hydraulic oil in the cooler core such that oil bypasses the cooler. This can lead to an overheat condition. The standard cooling system configuration allows the fan to spin regardless of ambient conditions, which draws outside air (as opposed to air from the engine compartment) through the side service doors and over the hydraulic oil heat exchanger core.

Solution:

Alter the cooling system using the following procedure. The hydraulically driven fan will be turned off via control oil bypass based on system conditions, which will help avoid "chilling" of the hydraulic oil in the heat exchanger.

NOTE: This modification IS NOT INTENDED TO 'THAW' A HYDRAULIC OIL COOLER ON A MACHINE THAT HAS BEEN SITTING UNUSED IN VERY COLD CONDITIONS FOR SEVERAL HOURS. This modification is intended only to prevent hydraulic system overheating while the machine is in use but with longer periods of hydraulic system idle time, such as waiting for a truck, etc.

NOTE: Slight modifications will be necessary if this kit is installed on machines with the reversing fan option.

HYDRAULIC SYSTEM SCHEMATIC

Use the following information to build the wiring harnesses.

(1) 30 - Tee to toggle switch.

(2) 87a.

(3) 85 - Tees to toggle switch.

(4) 86 - to temperature switch.

(5) 87 - to solenoid.

1.) 30 - to 86 on fan bypass relay.

2.) 87A - to engine temperature switch.

3.) 86 - to A/C compressor clutch.

4.) 85 - to frame rail ground.

5.) 87.

1. Install 9G-988e Breaker (9) with two 9X-8486 Screws by drilling two 4.8 mm (.19 in) dia. holes.

2. Mount a 3E-5239 Relay (12) to the panel. May mount with existing breaker (6).

3. Modify wiring panel assembly as needed to mount 8D-2676 Switch (11).

4. Connect Wire C (8) from 9G-9882 Breaker (9) to 8D-2676 Switch (11).

5. Connect 9G-9882 Breaker (9) and existing 9S-4693 Breaker (10) with Wire D (7) from location (A) to location (B).

6. Connect Wire Harness B (13) to 8D-2676 Switch (11).

7. Plug Wire Harness B (13) to 3E-5239 Relay (12).

8. Fabricate plate with publication number and install at location (C) near the 8D-2676 Switch.

9. After reinstalling the wiring panel, route Harness B toward rear of machine.

10. Plug Wire Harnesses A and B (14) together.

11. Remove 6V-9007 Elbow on inlet to hydraulic oil core. Install 8T-8901 Tee, 6V-1722 Reducer, and 8T-9705 Temperature Switch.

12. Route Wire Harness A to supplemental steering port on hydraulic tank and connect to temperature switch.

13. Remove 7W-6492 Plug (16) from the center port of the machine. Install 3B-7255 Reducer and 7N-7849 Temperature Switch.

14. Route Wire Harness A (17) to the temperture switch.

15. Route orange A/C Clutch wire of Harness A to the A/C Compressor by disconnecting the existing connector on the compressor and connecting the receptacle and plug to the clutch and existing A/C Clutch wire.

16. Route Wire Harness A (19) to back of machine.

17. Replace sure seal connector with one 3E-3364 Receptable, one 3E-3365 Wedge, and two 8T-8729 Pins (18).

18. Ground Wire Harness A to left frame rail (20) at same locations as the vehicle wiring harness.

19. Disconnect 117-7507 Hose Assembly (21) from the fan motor outlet port. Remove 6V-8637 Connector (22) with 3D-2824 and 6V-9746 Seals.

20. Disconnect 117-7506 Hose Assembly (24) from fan motor inlet port. Remove 6V-9007 Elbow (23) with 3D-2824 and 6V-9746 Seals.

21. Add 6V-8637 Connector (29) with 3D-2824 and 6V-9746 Seals in each port of 7T-6517 Valve. Mount 7T-6517 Valve (26) to Bar K with the solenoid (27) to the right side away from the fan motor using two 8T-5005 Bolts, two 8T-4121 Washers, and two 8T-4133 Nuts.

22. Weld Bar K (30) 100 mm (3.9 in) from the end of the support (31), after connecting the hoses. Pay attention to the clearance between Solenoid (27) and the hood support.

23. Connect solenoid (27) on 7T-6517 Valve to Harness A (28).