Oil Service Rating
The oil service rating is a set of letters printed on the
oil can to denote how well the oil will perform under
The American Petroleum
Institute (API) sets this performance standard.
The API system for rating oil classifies oil
according to its performance characteristics. The
higher rated oils contain additives that provide
maximum protection against rust, wear, oil oxidation,
and thickening at high temperatures. The oil service
ratings are as follows:
1. SAadequate for utility engines subjected to
light loads, moderate speeds, and clean
conditions. Contains no additives.
2. SBadequate for automotive use under
favorable conditions (light loads, low speeds,
and moderate temperatures) with relatively
short oil change intervals. Generally offers
only minimal protection to the engine against
bearing scuffing, corrosion, and oil
3. SCmeets oil warranty requirements for
1964 through 1967 automotive gasoline
4. SDmeets oil warranty requirements for
1968 through 1970 automotive gasoline
engines. Offers additional protection over SC
oils that are necessary with the introduction of
5. SEmeets oil warranty requirements for 1972
through 1979 automotive gasoline engines.
Stricter emission requirements created the
need for this detergent oil.
6. SFmeets oil warranty requirements for 1980
through 1988 automotive gasoline engines.
The SF oil is designed to meet the demands of
small, high-revving engines. A SF oil can be
used in all automotive vehicles requiring
7. SGmeets oil warranty requirements for
1989 through present automotive gasoline
engines. Contains more additives than SF oils.
Can be used as CC or diesel type oils. It is a
8. CAmeets all requirements for naturally
aspirated diesel engines operated on low sulfur
CBmeets all requirements for naturally
aspirated diesel engines operated on high
CCmeets all requirements for lightly
supercharged diesel engines.
CDmeets all requirements for moderately
supercharged diesel engines.
operator's manual provides the service rating
recommended for a specific vehicle. You can use a
better service rating than recommended, but NEVER a
lower service rating. A high service rating (SG, for
example) can withstand higher temperatures and loads
while still maintaining a lubricating film. It will have
more oil additives to prevent oil oxidation, engine
deposits, breakdown, foaming, and other problems.
LUBRICATING (OIL) SYSTEM
It must be remembered that the lubricating system
is actually an integral part of the engine and the
operation of one depends upon the operation of the
other. Thus the lubricating system, in actual practice,
cannot be considered as a separate and independent
system; it is part of the engine. The lubricating system
basically consists of the following:
Oil Panreservoir or storage area for engine oil.
Oil Level Gaugechecks the amount of oil in
the oil pan.
Oil Pumpforces oil throughout the system.
Oil Pickup and Strainerscarries oil to the
pump and removes large particles.
Oil Filtersstrains out impurities in the oil.
Oil Galleriesoil passages through the engine.
Oil Pressure Indicatorwarns the operator of
low oil pressure.
Oil Pressure Gaugeregisters actual oil
pressure in the engine.
Oil Temperature Regulatorcontrols engine oil
temperature on diesel engines.
The oil pan, normally made of thin sheet metal or
aluminum, bolts to the bottom of the engine block. It