Oil Consumption as an Overhaul
Indicator
Oil consumption, fuel consumption, and maintenance
information can be used to estimate the total
operating cost for your Caterpillar engine. Oil
consumption can also be used to estimate the
required capacity of a makeup oil tank that is suitable
for the maintenance intervals.
Oil consumption is in proportion to the percentage of
the rated engine load. As the percentage of the
engine load is increased, the amount of oil that is
consumed per hour also increases.
The oil consumption rate (brake specific oil
consumption) is measured in grams per kW/h (lb per
bhp). The brake specific oil consumption (BSOC)
depends on the engine load. Consult your Caterpillar
dealer for assistance in determining the typical oil
consumption rate for your engine.
When an engine's oil consumption has risen to three
times the original oil consumption rate due to normal
wear, an engine overhaul should be scheduled.
There may be a corresponding increase in blowby
and a slight increase in fuel consumption.
Overhaul Options
Before Failure Overhaul
A planned overhaul before failure may be the best
value for the following reasons:
• Costly unplanned downtime can be avoided.
• Many original parts can be reused according to the
standards for reusable parts.
• The engine's service life can be extended without
the risk of a major catastrophe due to engine
failure.
• The best cost/value relationship per hour of
extended life can be attained.
After Failure Overhaul
If a major engine failure occurs and the engine must
be removed from the hull, many options are
available. An overhaul should be performed if the
engine block or the crankshaft needs to be repaired.
If the engine block is repairable and/or the crankshaft
is repairable, the overhaul cost should be between 40
percent and 50 percent of the cost of a new engine
with a similar exchange core.
This lower cost can be attributed to three aspects:
• Specially designed Caterpillar engine features
• Caterpillar dealer exchange components
• Caterpillar Inc. remanufactured exchange
components
Overhaul Recommendation
To minimize downtime, Caterpillar Inc. recommends
a scheduled engine overhaul by your Caterpillar
dealer before the engine fails. This will provide you
with the best cost/value relationship.
Note: Overhaul programs vary according to the
engine application and according to the dealer that
performs the overhaul. Consult your Caterpillar
dealer for specific information about the available
overhaul programs and about overhaul services for
extending the engine life.
If an overhaul is performed without overhaul service
from your Caterpillar dealer, be aware of the following
maintenance recommendations.
Rebuild or Exchange
Cylinder Head Assembly, Cylinder Packs, Oil
Pump, and Fuel Transfer Pump
These components should be inspected according to
the instructions that are found in various Caterpillar
reusability publications. The Special Publication,
SEBF8029 lists the reusability publications that are
needed for inspecting the engine parts.
If the parts comply with the established inspection
specifications that are expressed in the reusable
parts guideline, the parts should be reused.
Parts that are not within the established inspection
specifications should be dealt with in one of the
following manners:
• Salvaging
• Repairing
• Replacing
Using out-of-spec parts can result in the following
problems:
• Unscheduled downtime
• Costly repairs
• Damage to other engine parts
• Reduced engine efficiency
• Increased fuel consumption
Reduced engine efficiency and increased fuel
consumption translates into higher operating costs.
Therefore, Caterpillar Inc. recommends repairing out-
of-spec parts or replacing out-of-spec parts.
SEBU7125-13
145
Maintenance Section
Overhaul Considerations
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