OiL Drain Interval Specification by cummins

Oil Drain Interval

Specifications

In recent years the trend toward extended oil drain intervals has been a confusing and controversial subject for the diesel engine user.Users have been influenced by numerous factors:improved oils, better filtration, more efficient engine design and the longer intervals being specified by several diesel manufacturers.

The energy crisis and the economy have also had an impact on this trend.The confusion however, continues.

The purpose of this program is to develop a better understanding of lubricating oils and filters and appreciation of Cummins oil drain interval specifications.

In the past 20 years, diesel engine manufacturers have experienced an over increasing demand for more power, longer engine life and lower operating costs. Meeting of many new engine technologies and designs

Cummins Engine Company has been the leader in these new developments in diesel power. Today, Cummins high performance engines are the standard of the industry.

Duding this same period many new developments were being made by the petroleum industry in engine lubricants. In the 1960s engine oils were generally designed for either gasoline or diesel engines.

In the early 1970s, there was a move towards universal oils. The development of universal blends required compromises in the basic oils performance. Although meeting the minimum requirements of both gasoline and diesel specifications, the new oil was not exceptionally good in either. The universal oils required a higher lever of detergent and dispersants which kept more insoluble and particulate matter in suspension, creating a new set of problems for the filters.

Universal oils, multi-grades, synthetics- the choice is endless. Some filter companies, lube oil producers and oil analysis labs also added to the confusion with claims of better and longer engine protection, thus recommending longer oil drain intervals.

The proper selection of lubricating oil and correct oil drain-filter change interval are the most important ingredients to prolonged engine life. Cummins Engine Company specifies that only a high quality lubricating oil conforming to these American Petroleum Institute classifications be used

The purpose of engine oil is to lubricate moving parts, provide internal cooling, aid as a combustion seal, keep the engine clean and protect internal parts from rust and corrosion.

Engine oil does not require draining because it wears out, but rather because it becomes contaminated to the point where it can no longer perform its intended.

Contamination of the oil is a result of engine operation. In moral diesel engine operation, a certain amount of combustion by-products pass into the crankcase. These blow-by gases, soot, partially burned fuel, acids, water and abrasives enter into and contaminate the oil.

Oil is blended with its additive package which is designed to combat these contaminants. It will generally consist of : dispersants, detergents, inhibitors and other additives.

The full-flow filtration system filters all oil circulated within the engine. Metallic and abrasive contaminants generated by normal operation and wear will be present in the oil. The full-flow filter will remove particles of this contamination which are larger than 40 micrometers or microns.

The bypass filter receives a smaller amount of lube pump oil flow, filters it and then returns it to the pan. The by-pass filter removes smaller size abrasive particles from the oil that the full-flow filter allows to pass. Its purpose is to maintain a low abrasive contamination level in the oil to prevent excessive engine wear.

The sludge contaminants held in suspension in the oil by the additive package are too small to be trapped by either filter and will continue to be circulated through the system. As the contamination level increases, the oil additive package will become depleted. That is, there will no longer be a sufficient supply of additives available to neutralize acids, prevent oxidation, break up the contaminants and held them in suspension.

When the additive package is depleted, the contaminants will start combining into larger particles and start setting in the engine. These larger particles of contaminants will now be large enough to be trapped by filters, and in a short amount of time will completely plug the filters. This condition is known as oil additive depletion or drop-out, and happens very rapidly after the additive package fails.

After additive package depletion occurs, the filter bypass valve will open allowing unfiltered oil to be circulated through the engine, and the chances for wear and damage to the engine insignificantly.

Since we know that oil contamination is the result of engine operation, under normal operating conditions there is a relationship between the amount of fuel consumed and the contamination generated. Oil has a limitation as to the amount of contaminants that can be absorbed and still function as intended.

However, during normal engine operation, oil is consumed or burned by the engine. Some of the contaminants suspended in this oil are also consumed. To keep the engine sump filled with oil, make-up oil must be added. The added oil provides the existing oil additive package with replenishment, thus allowing it to perform its intended function for a longer period.

The chart method for calculating oil drain intervals allows for establishing individual baseline oil drain intervals. Since engines and applications are different, the rate at which they consume fuel and contaminate oil will also be different. In order to calculate oil drain intervals using the chart method you must consider the application, fuel oil consumption rates and the actual lubricating system capacity.

An alternate to the Chart method is 10.000 miles, 250 hours or 6 months, which comes first.

A second alternate method of determining the oil change interval may be established through the use of oil analysis, if a properly designed test and evaluation program is carried out.

Spectrographic analysis determines only the wear metals and particulate matter level in lubricating oil. Therefore, Spectrographic analysis alone should not be used to determine the oil change interval.

To obtain more detailed information about lubricating oil drain intervals, consult the appropriate Cummins Operation and Maintenance Manual.

Under no circumstances does Cummins recommend extending the oil drain interval beyond 25.000 miles, 600 hours or 6 months, whichever comes first. This is true regardless of how much oil is added between oil changes. Now that you know more about oil and contaminants, Cummins oil drain specifications should be more understandable. Consider these facts:

Fact: years of extensive research and testing of engine wear have proven conclusively that a sharp increase in component wear occurs when the oil drain interval is extended beyond the safe limit.

Fact: If the oil drain interval is extended beyond the safe limits as calculated by the chart method, the oils additive package will be depleted. In developing the chart method Cummins considered all available lubricating oils.

Fact: To provide plugged or deteriorated filters, the filters must be charges at each oil drain interval. Simply changing the filters will not improve the oils additive package.

Although some engine manufacturers recommend extending oil drain intervals up to 100.000 miles, Cummins feels strongly that neither the short nor long term maintenance costs support these recommendation.

Cummins bases its oil drain specifications on oil contamination. This contamination occurs in all diesel engines, at varying rates, regardless of engine design. This holds true for two-cycle as well as four cycle engines.

An independent study conducted by Burlington Fleet Services supports Cummins position regarding oil drain interval vs. engine life. This study was based on maintenance records for over 2.000 diesel powered tractors operating in line-haul service.

In this study it was proven that in comparing trucks with oil change intervals less than 15.000 miles to trucks with oil change intervals exceeding 25.000 miles, the maintenance costs were fairly equal for the two groups up to 250.000 miles. Beyond 250.000 miles the engine maintenance costs for the group with the longer oil drain interval became significantly higher than the costs for the other group. The complete Burlington study in included in the recall booklet.

After years of experience as the leader in the diesel industry, Cummins feels strongly that its specifications are correct. As a result of following these specifications, both Cummins and its customers will benefit from longer engine life and cost efficient operations. Cummins Engine Company is not responsible for any failures or premature engine wear resulting from extending oil drain intervals beyond our specifications.