some info on eodi.
Technical Service Bulletin 98-1
Extended Oil Drain Intervals
Oil service intervals are pre-determined by engine manufacturers (OEM's) and
are designed to provide maximum engine protection under a wide variety of
conditions. While a majority of equipment owners follow these guidelines there is
a growing trend to extend oil service intervals beyond the OEM
recommendations; However, Extended Oil Drain Intervals (EODI) are not for
everyone. To fully understand the risks involved you must look at the key factors
affecting EODI's.
Engine lubricating oil is often referred to as the life blood of the engine. This
analogy is not made simply because the oil circulates through the engine but
more importantly because the oil performs critical functions necessary to
maintain engine performance and maximize useful service life. There are two
basic types of oil available today: Mineral and Synthetic oils. While these oils are
completely different in composition and beyond the scope of this service bulletin,
they must still meet the American Petroleum Institutes (API) qualification criteria
recommended by the engine manufacturers. There are many suppliers of oil in
the market today and not all meet the stringent requirements of the API standard.
Insuring your oil meets these requirements and understanding the factors
affecting the engine oil is the first step before extending your oil service interval.
Equipment operating extremes of Heat, Cold, Idle Time, Airborne Contaminants,
and Engine Load adversely affect engine oil. Excessive Heat will break down
engine oil and create deposits in the engine adversely affecting engine life.
Severe cold will limit the ability of the engine oil to lubricate at start-up and may
add unwanted moisture and unburned fuel to the oil. Extended Idle Time can
result in increased amounts of unburned fuel entering the oil resulting in oil
dilution and inadequate lubrication. Extreme dust conditions may tax even the
best air filtration system adding fine contaminants to the oil overloading the
additive package that keeps them in suspension. Heavy loads on the engine can
produce extra heat putting a greater demand on the cooling system and
increasing the importance of cooling system maintenance during EODI's. Off-road
operation will likely see more of these extremes than on-highway operation.
Engine designs today are cleaner burning with reduced emissions and make
excellent candidates for extended oil drain intervals; However, most customers
cannot afford to buy new equipment every year and normally fleets have a
mixture of equipment varying in vintage and service life. As piston rings and
valve guides wear in the engine, combustion by-products increase. These
combustion by-products end up accelerating oil additive depletion and create
harmful deposits on internal engine surfaces making the engine less likely to
benefit from an EODI.
Oil filters remove contaminants from the oil before they generate wear on engine
component surfaces. There are many filtration products offered in the industry
today with some claiming to allow for extended oil drain intervals. The fact is, the
filter alone will not extend the life of engine oil. The filter has one function, and
that is to filter contaminants from the oil. While most filters today do an excellent
job in filtering, the trend of extending oil drain intervals 2 to 3 times the normal
service interval has pushed the materials used in the manufacture of filters to the
limit. Adhesives, Rubber Compounds, Filter Media, and even the steel
construction in spin-on filters needs to be designed to meet the extended period
of time they are expected to be in service. Before considering an EODI make
sure the filter manufacturer will warranty their product when used in this manner.
If after considering all the factors affecting extended oil drain intervals you feel
your equipment is a candidate for EODI's you will need to develop a test program
to determine what length EODI is right for your equipment. To determine the
correct length EODI you must first implement an oil analysis program to develop
history on each piece of equipment scheduled for extended oil service. This will
allow you to determine if there is any usable life left in the oil. The primary
indicators will be Silicon (dirt), Viscosity (Oil Film Strength), Soot (Combustion
by-product), and Total Base Number (TBN). Most engine manufacturers have oil
analysis guidelines. Typically you will want to keep your silicon within 15ppm of
the initial oil sample, your Viscosity within the original oil grade specifications,
Soot below 3%, and the TBN number above 3. Each piece of equipment will vary
and the key is to look for trends in the analysis. If oil analysis indicates you can
extend your service interval you then need to move out in steps. Oil analysis
should continue at the normal service interval and in increments of 20%
thereafter until the analysis shows the useful life of the oil deteriorating. Once the
maximum limit on the oil is reached the change interval should be set at the
mileage of the previous sampling prior to indications of oil deterioration. Example:
Normal service interval = 16,000 miles (25,000 km). Oil analysis performed at
16,000 (25,000 km), 19,200 (30,000 km), 22,400 (35,000 km), 25,600 (40,000
km), and 28,800 (45,000 km). If oil analysis indicates problems at 28,800 (45,000
km) the change interval should be backed off to 25,600 miles (40,000 km). This
will allow for variables in operation and environment.
Extended oil drain intervals are not without risk and short term cost savings
benefits should be balanced equally with engine performance and reliability. With
all of the factors affecting the engine oil it is easy to see why OEM's have
traditionally been conservative in setting oil drain intervals. If you think your
equipment is a candidate for EODI program, do some research. Check with your
Filter, Engine, and Oil manufacturer for guidance. If you're not doing oil analysis,
start a program. Review your filtration package and most of all understand the
potential risks involved. If not properly implemented EODI short term savings are
offset by expensive repairs and downtime further down the road. Always dispose
of used engine oil and filters properly.