Early-Hour (Less Than 20,000 Miles) Coolant Leaks Caterpillar

Early-Hour (Less Than 20,000 Miles) Coolant Leaks

Usage:

ENGINES3176 (7LG),
3176B (9CK) TRUCK ENGINES

Problem:

Early hour coolant leaks have been found on 3176 (7LG) and 3176B (9CK) Truck Engines. The leak sources have included loose plugs or fittings, loose joints or defective gaskets, incorrectly assembled or defective O-rings, cracked water line components, and internal water pump seal failures. It is sometimes difficult, but VERY IMPORTANT to identify the exact source of the coolant leak. A number of water pumps have been mistakenly replaced when the leak actually resulted from an external source such as a pipe plug or gasket. However, early-hour water pump failures, identified by coolant leaking from the pump housing weep hole, have occurred in specific engine serial number ranges. These failures result from an over-concentration of the Supplemental Coolant Additive (SCA) which can produce leaks at the internal face seal. This situation requires special repair procedures as described below.

Solution:

If the engine has a coolant leak at less than 20,000 miles, first identify the exact source of the leak. If the leak is at an EXTERNAL source (fittings, plugs, gaskets, etc.), complete the repair as required. Report the incident and details to Service Engineering, Dale Lindenfelser, (309) 578-6433.

If the coolant leak is an INTERNAL water pump defect (coolant coming out the pump weep hole), proceed as follows depending on the engine serial number range:

A.3176 (7LG12000-21768) OR 3176B (9CK647-1665)

1.Obtain a coolant sample (3 or 4 oz) and mail to:

Caterpillar, Inc.
Bldg VV, Location Moss 40
Old Galena Road, Dock 55
Mossville, IL 61552
Atten: D. Lindenfelser, (309) 578-6433

2.Drain the coolant, and discard in an appropriate manner.

3.Fill the system with fresh water and 20 percent (by volume) of Caterpillar Quick Flush Cleaner. This is 2 gallons of Cleaner for a 10 gallon system. Do NOT exceed 25 percent cleaner volume. Run the engine for at least 90 minutes after reaching normal operating temperature. Be sure the cleaning solution is flowing through the heater core and spin-on coolant conditioner element (if equipped). Caterpillar Quick Flush Cleaner is available as follows:

4.Drain the cooling system and dispose of the cleaning solution.

5.Flush out the system with fresh water. If a spin-on conditioner element is present; remove the element, drain and rinse with water, and re-install on the engine. Do NOT install a fresh precharge element.

6.Replace the water pump.

7.Refill the cooling system with a 50/50 mix Caterpillar Antifreeze and acceptable water.

8.Report the incident and details to Service Engineering, Dale Lindenfelser, (309) 578-6433.

B.3176 (7LG21769-UP) OR 3176B (9CK1666-UP)

1.Complete the repair following the normal procedures. DO NOT perform the drain/flush/clean/refill procedure.

2.Report the incident and details to Service Engineering, Dale Lindenfelser, (309) 578-6433.

Please share this information with your TEPS Dealers.