API CG-4 oils are the first oils that are required to pass
industry standard tests for foam control and viscosity shear
loss. API CG-4 oils must also pass tests that were developed
for corrosion, wear and oxidation.
API CF-4 - These oils service a wide variety of modern diesel
engines. API CF-4 oils provide more stable oil control and
reduced piston deposits in comparison to API CF and the
obsolete CE and CD classifications of oil. API CF-4 oils
provide improved soot dispersancy in comparison to API CF
and obsolete CD oils. The API CF-4 classification was
developed with a 0.40 percent sulfur diesel fuel. This
represents the type of diesels that are commonly available
Do not use single grade API CF oils or use
multigrade API CF oils in Caterpillar Direct
Injection Commercial Diesel Engines.
Some commercial oils that meet the API classifications may
require reduced oil change intervals. To determine the oil
change interval, closely monitor the condition of the oil and
perform a wear metal analysis. Caterpillar's SOS oil analysis
program is the preferred method.
Failure to follow these recommendations can cause
shortened engine life due to carbon deposits and/or
Total Base Number (TBN) and Fuel Sulfur Levels for Direct
Injection (DI) Diesel Engines
SMCS Code: 1348
The Total Base Number (TBN) for an oil depends on the fuel
sulfur level. For direct injection engines that use distillate fuel,
the minimum TBN of the new oil must be 10 times the fuel
sulfur level. The minimum TBN of the oil is five (5) regardless
of fuel sulfur level. Illustration 125 demonstrates the TBN.
TBN by ASTM D2896"
Percentage of fuel sulfur by weight
TBN of new oil
Change the oil when the TBN deteriorates to 50 percent
of the original TBN.
Use the following guidelines for fuel sulfur levels that exceed
Choose an oil with the highest TBN that meets one of
these classifications: EMA LRG-1, API CH-4, API CG-
4, and API CF-4.
Reduce the oil change interval. Base the oil change
interval on the oil analysis. Ensure that the oil analysis
included the condition of the oil and a wear metal
Excessive piston deposits can be produced by an oil with a
high TBN. These deposits can lead to a loss of control of the
oil consumption and to the polishing of the cylinder bore.
Operating Direct Injected (Dl) diesel engines with fuel
sulfur levels over 1.0 percent may require shortened oil
change intervals in order to help maintain adequate wear
SMCS Code: 4250; 4300; 5050; 5095