Identifying Oil Leaks on Certain 3500 Mining Machine Engines {1151, 1348} Caterpillar

Engine

3512C (S/N: MLM1-UP)

Hydraulic Shovel

6060 (S/N: DHN1-UP)

6060 FS (S/N: DH31-UP)

Motor Grader

120H (S/N: 9YR1-UP)

Off-Highway Truck/Tractor

777D (S/N: AGC1-UP; FKR1-UP; 3PR1-UP; AGY1-UP)

785 (S/N: 8GB1-UP)

785B (S/N: 6HK1-UP)

785C (S/N: 1HW1-UP; APX1-UP)

785D (S/N: DMC1-UP; MSY1-UP)

785G (S/N: TRG1-UP; RTL1-UP)

789B (S/N: 7EK1-UP)

789C (S/N: 2BW1-UP)

789D (S/N: SPD1-UP; SHH1-UP)

793 (S/N: 3SJ1-UP)

793B (S/N: 1HL1-UP)

793C (S/N: 4AR1-1; ATY1-UP; 4GZ1-UP)

793D (S/N: FDB1-UP)

797 (S/N: 5YW1-UP)

797B (S/N: JSM1-UP)

Wheel Loader

994D (S/N: 3TZ1-UP)

994F (S/N: 4421-UP)

994K (S/N: MM91-UP; MRK1-UP; SMX1-UP)

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

Dealers are performing repairs that do not resolve oil leaks. After additional inspections the source of the oil leak is found to be occurring at higher locations on the engine or upstream of the air currents around the engine.

Solution

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Do not operate or work on this product unless you have read and understood the instruction and warnings in the relevant Operation and Maintenance Manuals and relevant service literature. Failure to follow the instructions or heed the warnings could result in injury or death. Proper care is your responsibility.

Review the following information when troubleshooting the oil leaks. Consider using a black light and 1U-5573 Additive (Dye) to check for the source of leaks. Consider that gravity and air flow will distribute oil in areas that may be far from the source. Pan rails, block to housing joints and other interfaces that run parallel to gravity, or to airflow are very effective at moving oil away from the source. Inspect all sealing areas including the alternator and air conditioner pulley seals, covers, adapters, and pumps for areas that indicate oil leaks - wet with oil, or are holding large clumps of dust. Follow the oil upward, and into air flow from the cooling fan, as the highest and closest oil to the air flow will probably be the source of the leak. Wash the engine, and check that the areas with oil signs are now clean. Run the engine for a few minutes at a time then recheck for indications of the leak. Always check carefully at locations that were previously wet, and particularly at the highest points. Ensure that the areas closest to the air flow or higher on the engine remain clean and dry.

Illustration 1	g06418151
Oil signs at alternator drive pulley.

Illustration 2	g06418155
Oil signs at alternator drive pulley.

Oil migration from the pulley onto adjacent areas due to gravity, engine vibrations, and air flow from engine fan.

Illustration 3	g06418190
Oil and dust present below alternator drive pulley.

Illustration 4	g06418194
Oil and dust present below alternator drive pulley.

Illustration 5	g06418196
Oil and dust present below alternator drive pulley.

Oil runs down between pump adapter and front housing.

May falsely appear to be a sealing issue with the adapter to housing seal, or the pump to adapter seal.

Illustration 6	g06418198
Oil present at pump drive adapter and front housing interface.

What appears to be a leak between the front housing and adapter is actually oil that ran down between the cover and housing.