1980/06/23 Caterpillar

All Caterpillar Engines

Troubleshooting to find the source or sources of leakage of coolant into the lubrication system can be a long and difficult procedure. But several easy tests can be made to show if some of the areas are possible sources of leakage.

Scheduled Oil Sampling, for those engines which have this service, will tell if there is coolant in the lubrication system.

For engines which do not have Scheduled Oil Sampling, look for indications of this leakage. The indications are ...

1. Sludge (dirt and debris) in the oil and oil filter;

2. Oil which has a milky (white) color;

3. Too much water vapor from the crankcase breather; and

4. White smoke from the exhaust.

If any of the above indications are present, take a small amount of oil for analysis.

The most common sources of leakage are ...

1. Around the O-ring seals on the cylinder liners;

2. Through cracks and holes in the cylinder liners;

3. Through cracks and holes in the cylinder heads and block;

4. Around the cylinder heads and spacer plate gasket;

5. Around the air compressor cylinder head;

6. At the oil cooler; and

7. At the water pump.

8. Through porous (with small openings through which liquids and gases pass) center housings in water-cooled turbochargers.

If there is coolant leakage into the engine's lubrication system, check for oil and combustion gases in the radiator. Run a "bottle test" to check for combustion gases, and have an analysis made of the coolant. Instructions for the "bottle test" are given on pages 14 and 15 of "Know Your Cooling System" Form No. SEBD0518

If there is no oil or gas in the radiator, there is no coolant leakage ...

1. At the oil cooler;

2. From the high pressure oil passages that run through the coolant jackets in the cylinder block and heads;

3. Around the air compressor head;

4. From the tops of the cylinder liners; and

5. From the areas of the cylinder heads above and near the liners.

Next, start the engine and let it get warm to put pressure in the cooling system. Shut down the engine, drain the oil and remove the oil pan.

Carefully check ...

1. The bottoms of the cylinder liners for leakage around or through the liners and/or pass around the O-ring seals;

2. Front gear train; and

3. Rear gear train.