Page 165 - 05. Subyek Teknik Mesin - Automobile Mechanical and Electrical Systems Automotive Technology Vehicle Maintenance and Repair (Vehicle Maintenance Repr Nv2) by Tom Denton

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Engine systems 149

Figure 2.134 API service symbol example (donut)

multigrade oil. The two numbers used are individually defi ned by SAE for single-
grade oils. Therefore, an oil labelled as 10 W–30 must pass the viscosity grade
requirement for both 10 W and 30 grades.

2.2.6.2 API
The American Petroleum Institute (API) sets a minimum for performance
standards for lubricants. Lubricant base stocks are categorized into fi ve groups
by the API. Group I base stocks, for example, are composed of fractionally
distilled petroleum which is further refi ned with solvent extraction processes to
improve certain properties such as oxidation resistance and to remove wax. Other
groups describe further refi nements and bases. Group III relates to synthetic oils
and group V is used for anything that does not fi t into the other groups.
The API service classes use two general classifi cations: S for ‘service’ (originating
from spark ignition) and C for ‘commercial’ (originating from compression ignition).

Engine oil that has been tested and meets the API standards may display the API
Service Symbol, also known as the ‘donut’ ( Fig. 2.134 ).
The latest API service standard designation is SN for gasoline automobile and
light truck engines. The SN standard refers to a group of laboratory and engine
tests, including the latest series for control of high-temperature deposits. Current
API service categories include SN, SM, SL and SJ for petrol/gasoline engines.
There are six current diesel engine service designations: CJ-4, CI-4, CH-4,
CG-4, CF-2 and CF. In addition, API created a separated CI-4 PLUS designation
in conjunction with CJ-4 and CI-4 for oils that meet certain extra requirements,
and this marking is located in the lower portion of the API service symbol.
Some oils conform to both the petrol/gasoline and diesel standards. It is
the norm for all diesel-rated engine oils to carry the corresponding gasoline
specifi cation.

2.2.6.3 ILSAC
The International Lubricant Standardization and Approval Committee (ILSAC)
also has standards for motor oil. Introduced in 2004, GF-4 applies to SAE
0 W–20, 5 W–20, 0 W–30, 5 W–30 and 10 W–30 viscosity grade oils. A new set
of specifi cations, GF-5, took effect in October 2010. The industry has one year
to convert their oils to GF-5 and in September 2011, ILSAC will no longer offer
licensing for GF-4. In general, ILSAC works with API in creating the newest oil