A guide to API Specs

A guide to API Oil Specs

Petrol Engines
SN
Introduced in October 2010 for 2011 and older vehicles
SN is design to provide improved high temperature deposit protection for pistons, better sludge control, and seal compatibility.
API SN with Resource Conserving matches ILSAC GF-5 by combining API SN performance with improved fuel economy, turbocharger protection, emission control system compatibility, and protection of engines operating on ethanol-containing fuels up to E85.
SM
Introduced on 30 November 2004
SM oils are designed to provide improved oxidation resistance, improved deposit protection, wear protection, and low-temperature performance over the life of the oil.
Some SM oils also meet the latest ILSAC specification qualify as Energy Conserving. They may be used where SJ and SL earlier categories are recommended.
SL
2001 Gasoline Engine Service
Adopted in 2001 for use in gasoline engines in present and earlier passenger cars, sports utility vehicles, vans and light trucks operating under vehicle manufacturers recommended maintenance procedures.
SL category oils may be used where API Service Category SJ and earlier categories are recommended.
SJ
1997 Gasoline Engine Service
Adopted in 1996 for use in service typical of gasoline engines in present and earlier passenger cars, vans, and light trucks operating under manufacturers recommended maintenance procedures.
They may be used where API Service Category SH and earlier categories are recommended.
SH
Obsolete
For model 1996 and older engines.
SG
Obsolete
For model 1993 and older engines.
SF
Obsolete
For model 1988 and older engines.
SE
Obsolete
For model 1979 and older engines.
SD
Obsolete
For model 1971 and older engines.
SC
Obsolete
For model 1967 and older engines.
SB
Obsolete
For older engines. Use only when specifically recommended by the OEM.
SA
Obsolete
For older engines; no performance requirement. Use only when specifically recommended by the OEM.
Diesel Engines
CJ-4
Current – 2006
Introduced in 2006 for high-speed four-stroke engine and designed to meet the 2007 on-highway exhaust emission standards.
CJ-4 oils are compounded for use in all applications with diesel fuels ranging in sulphur content up to 500ppm. However, use of these oils with greater than 15ppm sulfur fuel may impact exhaust after treatment system durability and/or oil drain intervals.
CJ-4 oils are effective at sustaining emission control system durability where particulate filters and other advanced after treatment systems are used.
CJ-4 oils exceed the performance criteria of CF-4, C-4, AH-4 and C-4.
CI-4 Plus
Current – 2004
Used in conjunction with API C-4, the CI-4 PLUS designation identifies oils formulated to provide a higher level of protection against soot-related viscosity increase and viscosity loss due to shear in diesel engines.
CI-4
Severe-Duty Diesel Engine Service
Designed to meet the 2004 exhaust emission standards and introduced in 2002, for use in high speed, four-stroke cycle diesel engines .
These oils are compounded for use in all applications with diesel fuels ranging in sulfur content up to 0.05% by weight. They are especially effective at sustaining engine durability where Exhaust Gas Recirculation (EGR) and other exhaust emission components may be used. Optimum protection is provided for control of corrosive wear tendencies, low and high temperature stability, soot handling properties, piston deposit control, valve train wear, oxidative thickening, foaming and viscosity loss due to shear.
CI-4 oils are superior in performance to those meeting API CH-4, CG-4 and CF-4.
CH-4
Severe-Duty Diesel Engine Service
This service oils are suitable for high speed, four-stroke diesel engines designed to meet 1998 exhaust emission standards and are specifically compounded for use with diesel fuels ranging in sulfur content up to 0.5% weight. CH-4 oils are superior in performance to those meeting API CF-4 and API CG-4 and can effectively lubricate engines calling for those API Service Categories.
CG-4
Obsolete
This category describes oils for use in high speed four-stroke-cycle diesel engines used in both heavy-duty on-highway (0.05% wt sulfur fuel) and off-highway (less than 0.5% wt sulfur fuel) applications. CG-4 oils provide effective control over high temperature piston deposits, wear, corrosion, foaming, oxidation stability, and soot accumulation. These oils are specially effective in engines designed to meet 1994 exhaust emission standards and may also be used in engines requiring API Service Categories CD, CE, and CF-4. Oils designed for this service have been in existence since 1994.
CF-2
Obsolete
Introduced in 1994 for severe duty, two stroke motorcycle engines. Can be used in place of CD-II.
CF
Obsolete
Introduced in 1994 and may be used when API Service Category CD is recommended. For off-road, indirect-injected and other diesel engines including those using fuel over0.5% weight sulphur
CF-4
Obsolete
For high speed, four-stroke cycle diesel engines  exceed the requirements for the CE category.
CE
Obsolete
Can be used in place of CC and CD, it was Introduced in 1987 for high-speed four-stroke naturally aspirated and turbo engines, that have been manufactured since 1983
CD-II
Obsolete
Introduced in 1987 for two-stroke motorcycle engines
CD
Obsolete
Introduced in 1955 for certain naturally aspirated and turbo engines.
CC
Obsolete
Introduced in 1961
CB
Obsolete
Introduced in 1949 for moderate-duty engines.
CA
Obsolete
Widely used in the 1940s and 1950s and should only be used when specifically recommended by the OEM.
For more on oil specs, take a look at: http://www.oilspecifications.org/api_eolcs.php

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