Why Does Diesel Mix With Engine Oil On My Diesel Engine Generator?

 

What causes the engine oil in my diesel engine generator to mix with diesel?

Fuel that contains sulfur compounds is used in diesel engines. The fuel burns erratically due to these sulfur compounds, producing soot particles. The lubricating oil is thus contaminated when the soot particles get inside. This contamination makes the oil less effective and causes the engine to wear out more quickly.

As the problem of acid rain became more prominent over time, the petroleum firm was required to reduce the sulfur level of diesel, which impacted diesel's lubricity. This action impacts these Pumps because their purpose is to operate on highly lubricious fuel.

The answer lies in the fuel system.

If you notice that diesel mixes with the engine oil on your diesel engine generator, there are three possible reasons. First, the manual fuel pump(Hand lift pump)  may not work correctly. Second, the seal(O ring) at the drive shaft of the injection fuel pump may be faulty. Thirdly, the injectors may be leaking diesel after the engine shuts down.

To determine whether either of these issues is causing the problem, check the following:

1) Check the manual hand lift fuel pump and replace it if necessary.

2) Check the seal(O ring) at the drive shaft of the injection fuel pump and replace it if necessary.

3) Check the injectors. Take them out for servicing or replace them, as the case may be.

MANUAL FUEL PUMP

Engines designed with a mechanically driven lift pump on the side of the engine block may be affected by diesel going into the engine oil through the faulty pump diaphragm. The leaking diagram will let diesel into the sump to dilute the engine oil.

INJECTION PUMP

For diesel to get to the combustion chamber to be utilized by the diesel engine generator to produce electricity, it has to be under pressure—the pressure needed by the generator with the help of an Injection pump. 

The injection pump is part of the gear train and rightly done so to help it achieve its pumping pressure. These gears are lubricated with engine oil to reduce heat, wear, and tear. 

The Injection pump has a relationship with diesel and engine oil and maintains this healthy relationship, a seal(O ring) for the shaft comes in. 

Since this seal(O ring) separates the diesel and engine oil if faulty will let diesel into the engine oil via the gear train. If you have to solve this problem, the injection pump should be removed from the engine (after nothing, the engine timing) for the seal to replace. The injection pump will be pressure tested, the seal replaced if need be, and returned for reinstallation.

INJECTORS

The fuel system is highly pressurized, and the injectors can bleed the pressure off. It results in diesel dumping directly into pistons and dripping past the rings to the sump after the generator is off.

To decipher this, check the injectors and do a compression test on all the engine cylinders. Since you have diesel down there for some time and washing lubricant, wear and tear are likely to occur.

Dilution of engine oil by diesel in a diesel engine generator can be challenging. Following the above suggestions from the list challenging to the most one, can significantly help. Make sure you carry out regular maintenance as advised by the manufacturer.