Water Pump on Certain C2.2 Engines {1361, 7555} Caterpillar

Engine

C2.2 (S/N: C6M1368-1368,3955-3955,3976-3976,4230-4234,4238-4247,4640-4640,4651-4653,4698-4698,4709-4712,4725-4727,5041-5048,5051-5058,5635-5644,6335-6339,6488-6492,6849-6849,6864-6864)

Introduction

The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below.

Problem

There have been isolated instances of coolant leakage from the bottom of the water pump at low engine hours on certain C2.2 engines. The affected engines have a low mounted fan on 340-5781 Cylinder Block Gp or 420-6407 Cylinder Block Gp.

Solution

The water pump contains a rotary seal. Engine coolant is used to lubricate the rotary seal and maintain an adequate sealing film to reduce heat generation. During normal operation, a small amount of coolant and vapor will pass over the seal into a chamber within the pump. The chamber allows the coolant to evaporate through the weep hole and the vent holes in the pump.

In some ambient conditions and operating conditions, not all the liquid will evaporate. In this situation, the liquid can be expelled through the weep hole. A loss of less than one drop of coolant every 10 seconds from the weep hole is acceptable.

The rotary seal within the pump can trap debris between the seal faces. The seal will usually expel the debris within 30 hours of operation. During this period, there may be a significant loss of coolant through the weep hole.

If there is insufficient coolant flow, the rotary seal can be damaged. In this situation, the leak rate from the weep hole will be greater than 1 drop every 10 seconds.

Required Information

1. Take photographs of the engine bay area, the engine cooling fan, and the area where the water pump is leaking. Ensure that the photographs are clear. Also, ensure that the photographs have a file name that contains the CPI issue number, the engine serial number, and the date of repair.

2. If possible, take clear photographs of the machine and engine data plates. If photographs are not possible, record the machine model, the machine serial number, the engine arrangement, and the engine serial number in a Word document.

3. Record the following information at time of repair:

   • Photograph of installed engine cooling fan

   • Cooling fan part number and model information, if available

   • Installed air flow direction, that is, Puller-type or Pusher-type

4. Provide a copy of the full service history of the engine. This copy should include the following items:

   • Engine oil specification and grade

   • Oil sample interval

   • Oil filter replacement history

   • Fuel filter replacement history

   • Fan belt tensioning history

   • Details of any cooling system repairs, including any water pump replacement, that is not recorded on SIMSi.

Procedure

The following information applies to 371-0183 Water Pump and 439-4992 Water Pump.

1. If a coolant leak is suspected near the water pump, determine if the leak is a new event. Remove any coolant stains from the water pump and the front of the engine.

2. Check the coolant level. Refer to "Operation and Maintenance Manual", Cooling System Coolant Level - Check.

3. Monitor the area around the water pump regularly for signs of a coolant leak.

4. Monitor the leak rate from the weep hole in the water pump. If the leak rate is greater than 1 drop in 10 seconds or does not stop after 30 hours of operation, continue with this procedure.

5. Record the breakaway torque and scribe line torque on bolt (1), bolt (2), bolt (3), bolt (4), and nut (5) as follows:
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   Illustration 1	g06176096

   Note: During the following process, use a dial indicator torque wrench that is able to measure a torque of approximately 10 N·m (89 lb in) accurately.

   1. Install the torque wrench and socket on bolt (1).

   2. Use a suitable white marker to apply a clear mark on the side of the socket and onto the water pump body.

   3. Noting the release torque, loosen bolt (1) through 30 to 90 degrees.

   4. Torque tighten bolt (1) until the marks on the socket and pump body are aligned. Note the required torque.

   5. Repeat Steps a. through d. for bolt (2), bolt (3), bolt (4), and nut (5).
   Show/hide table

   Illustration 2	g06176152
   423-5611 Gasket

   Show/hide table

   Illustration 3	g06176175
   Water pump fastener torque tightening sequence

   Note: During installation of a replacement water pump, ensure that 423-5611 Gasket is used with 439-4992 Water Pump. Photograph the old gasket and the back plate of the old water pump after removal. Ensure that both parts are retained.

   Note: During installation of the replacement water pump, ensure that the torque tightening process below is followed. Refer to Illustration 3.

6. If the leakage from the water pump is not within limits, install a new water pump. Refer to "Disassembly and Assembly", Water Pump - Remove and Install (C1.1, C1.5, C1.6 and C2.2 Engines).

   Tighten nut (1) to a torque of 5 N·m (44 lb in). Tighten in sequence bolt (2), bolt (3), bolt (4), and bolt (5) to a torque of 5 N·m (44 lb in).

   Tighten nut (1) to a torque of 10 N·m (89 lb in). Tighten in sequence bolt (2), bolt (3), bolt (4), and bolt (5) to a torque of 10 N·m (89 lb in).

   Before returning the engine to service, check for the following possible causes of insufficient coolant flow to the water pump seal:

   • Low coolant level. Refer to the OEM documentation for the procedure to check the coolant level in the system.

   • Maintenance Interval Schedule adherence. Refer to Operation and Maintenance Manual, Maintenance Interval Schedule.

   • Air in the cooling system that was not purged during fill. Start and run the engine at low idle. Increase the engine rpm to 1500 rpm. Run the engine at high idle for 1 minute to purge the air from the cavities of the engine block.

   • Leaks in the cooling system. Refer to Systems Operation, Testing and Adjusting, Cooling System - Inspect.

   • High coolant temperature. Refer to Systems Operation, Testing and Adjusting, Troubleshooting.

CPI Feedback

The CPI Team needs information on the location of the machine and the type of installation that is causing water pump leaks.

Send the required information and the recorded data together with the TIB Media Number M0081005 and CPI Number 383108 to the dealer Technical Communicator (TC). Request that the dealer TC submit the information through CPI Feedback within the Service Information Management System (SIMSi) Refer to Illustration 4.

Illustration 4	g06176186