Mineral Oils
6. Record the rod A reading in column 3 of the
diesel engine lube oil testing log. (We will
Mineral oils, commonly called 2190 TEP, are
examine this log later in this chapter.) Record
extensively used throughout naval engineering plants.
the used oil rod reading in column 4 of the oil
These oils are commonly used in your ship's main
test log.
You can now repeat the process if you are using
and generators.
another used oil sample in tube 2. When you have
Earlier in this section, we discussed the procedures
completed the tests, wipe the rods and the balls and drain
you should use for sampling oils. If a mineral oil sample
the tubes thoroughly. You must make certain to do this
fails your visual inspection or remains hazy after
between each test. Place the comparator back in its
settling, you will need to perform additional tests. The
storage case.
tests you will perform on mineral oils are for
The proper analysis of the test results depends upon
transparency and BS&W.
the design and size of the engine from which you took
In sampling and testing mineral oils, you should be
the sample. You can generally use the following
aware of some special characteristics. Sometimes the
standards:
chemical makeup of a mineral oil will cause a good oil
not to be clear and bright at 77F (25C). This usually
The normal range of fuel dilution will be within
happens when the oil is contaminated with trace
0.5 to 2.0 percent.
amounts of water. After the oil is heated, it becomes clear
Fuel dilution in the range of 2.0 to 5.0 percent
and bright. Consequently, if you are sampling a
indicates either a fuel jumper line leak or faulty
MIL-L-17331 (2190 TEP) lube oil and your oil sample
injection equipment.
is not clear and bright at 77F (25C), use a water bath
to heat the oil to 120F (48.8C). For the water bath, you
Fuel dilution greater than 5.0 percent should
will need a container of water and a heat source, such as
cause you to be seriously concerned about the
a hot plate. You can also use a deep sink or pot filled
fitness of the engine. In addition to checking for
with hot water. Place the sample bottle in the water and
jumper line leaks and faulty injection
heat the oil until it reaches 120F (48.8C). Observe the
equipment, inspect several of the engine
oil sample periodically. If the oil becomes clear and
bearings for abnormal or excessive wear. If the
bright when it reaches 120 (48.8C), it is satisfactory
bearings are worn, you will need to make further
for use. If the oil fails to become clear and bright after
inspections to determine both the extent of
it reaches 120F (48.8C), use the following guidelines:
bearing damage and the proper repair actions.
1. If the equipment has online purification
The standards of the test are logical if you just think
capability, have the oil purified. If the oil is still not clear
and bright after three passes through the purifier, change
about how the test works. In the case of fuel dilution, the
it.
higher the fuel dilution (oil thinning), the faster the rod
will move down in the used oil than it will in the new
2. If the equipment does not have online
oil. Oil thickening, however, is just the opposite. The
purification capability and you discover particulate
carbon and sediment picked up by the oil will cause the
matter in the sample, perform the BS&W test. If the
oil to become thicker and will cause engine damage if
sample is not clear and bright, perform the transparency
the oil is not changed.
test.
TYPES OF OILS
Synthetic Oils
We have just discussed the basic tests you will be
Synthetic oils are found in shipboard cooling
required to perform on oil samples. We will now talk
systems. You will routinely make visual inspections of
about the different oils you will test and how the
synthetic oils during sampling. In addition to
characteristics and testing requirements will differ
transparency and BS&W tests, there is one other
depending on the type of oil and the type of equipment
shipboard test you will need to be familiar with for
using it. Since they are the most commonly used oils on
synthetic oils, the test for mineral oil contamination. In
your ship, we will discuss mineral oils, or 2190 TEP,
performing this test, you should use the procedure we
described earlier.
first.
