3126B Marine Engines Caterpillar

Refer to Illustration . The engine oil pressure is in the "Low Oil Pressure Derate Region" for 30 seconds.

Illustration 1	g01128507
Region for the low oil pressure derate (X) Engine speed (rpm) (Y) Engine oil pressure (kPa)

System Response:

The ECM will log the event.

Engine power is reduced.

Test Step 1. Check the Engine's Lubrication System

1. Check the engine oil level. If the oil level is below the oil pump's supply tube, the oil pump will not have the ability to supply enough lubrication to the engine components. If the engine oil level is low, add engine oil in order to obtain the correct engine oil level.

2. Check the engine oil pump for the following problems:

   1. Air leakage in the supply side of the oil pump will also cause cavitation and loss of oil pressure. Check the supply side of the oil pump and make necessary repairs.

   2. Oil pump gears that have too much wear will cause a reduction in oil pressure. Repair the engine oil pump.

   3. If the engine is equipped with a scavenge pump, the scavenge pump may not be supplying oil to the main engine oil pump.

3. The inlet screen of the oil suction tube for the engine oil pump can have a restriction. This restriction will cause cavitation and a loss of engine oil pressure. Check the inlet screen on the oil pickup tube and remove any material that may be restricting engine oil flow. Low engine oil pressure may also be the result of the oil pickup tube that is drawing in air. Check the joints of the oil pickup tube for cracks or a damaged O-ring seal.

4. If the engine oil bypass valves are held in the open position, a reduction in the oil pressure can be the result. This may be due to debris in the engine oil. If the engine oil bypass valves are stuck in the open position, remove each engine oil bypass valve and clean each bypass valve in order to correct this problem. You must also clean each bypass valve bore.

5. Engine oil that is contaminated with fuel or coolant will cause low engine oil pressure. High engine oil level in the crankcase can be an indication of contamination.

6. Excessive clearance at engine bearings will cause low engine oil pressure. Check the engine components for excessive bearing clearance.

7. An oil line that is open, broken, or disconnected will cause low engine oil pressure.

Expected Result:

An inspection of the engine's lubrication system indicated a problem.

Results:

• OK - There is a problem in the engine's lubrication system.

  Repair: Repair the problem. Ensure that the repair eliminates the problem.

  Stop.