What Is API Engine Oil? Petrol Engine & Diesel Engine

API SERVICE CLASSIFICATION FOR PASSENGER CAR ENGINE OIL

API Service Categories

The next “code” to look for is the API Service Classification. Although it might appear complicated to understand at the start, it is really a simple system to get your arms around. Think of it this way, when cars were first built, the oil they required needed an API SA Service Classification. From there, it moved to SB, SC, SD, and so on (skipping only SI and SK).

So if you buy an engine oil meeting only API SA, it’s an engine oil formulated for use in vehicles built in the 1930s. And SA is not hard to find mixed in with SM on the shelves at c-stores and others. Furthermore, it’s also not hard to find SF, SJ and other API Service Categories on the shelves. Also, don’t let prices guide you. Engine oils with a Service Classification prior to SN (including SA) are often priced close to that of API SN. 

The service rating of passenger car and commercial automotive motor oils is classified by the American Petroleum Institute (API).

American Petroleum Institute Gasoline Engine Oil Service Classifications

Category
Status
Service
SN
Current
Introduced in October 2010 for 2011 and older vehicles, designed to provide improved high temperature deposit protection for pistons, more stringent 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
Current
For 2010 and older automotive engines.
SM
Current
For 2004 and older automotive engines.
SJ
Current
For 2001 and older automotive engines.
SH

Obsolete
 
SG

Obsolete
 
SF

Obsolete
 
SE

Obsolete
Caution– Not suitable for use in gasoline-powered automobile engines built after 1979.
SD

Obsolete
Caution– Not suitable for use in gasoline-powered automobile engines built after 1971. Use in modern engines may cause unsatisfactory performance or equipment harm.
SC

Obsolete
Caution– Not suitable for use in gasoline-powered automobile engines built after 1967. Use in modern engines may cause unsatisfactory performance or equipment harm.
SB

Obsolete
Caution– Not suitable for use in gasoline-powered automobile engines built after 1951. Use in modern engines may cause unsatisfactory performance or equipment harm.
SA

Obsolete
Caution– Not suitable for use in gasoline-powered automobile engines built after 1930. Use in modern engines may cause unsatisfactory performance or equipment harm.

API SERVICE CLASSIFICATION FOR DIESEL ENGINE OIL

What is API? Diesel engine

API FA-4 and the FA-4 Donut identify certain XW-30 oils specifically formulated for use in select high-speed four-stroke cycle diesel engines designed to meet 2017 model year on-highway greenhouse gas (GHG) emission standards. API FA-4 oils are not interchangeable or backward compatible with API CK-4, CJ-4, CI-4 PLUS, CI-4, and CH-4 oils. Refer to engine manufacturer recommendations to determine if API FA-4 oils are suitable for use.

The service rating of passenger car and commercial automotive motor oils is classified by the American Petroleum Institute (API).

American Petroleum Institute Diesel Engine Oil Service Classifications

Category
Status
Service
CJ-4
Current
For high-speed four-stroke cycle diesel engines designed to meet 2010 model year on-highway and Tier 4 nonroad
exhaust emission standards as well as for previous model year diesel engines. These oils are formulated for use in all
applications with diesel fuels ranging in sulfur content up to 500 ppm (0.05% by weight). However, the use of these oils
with greater than 15 ppm (0.0015% by weight) sulfur fuel may impact exhaust aftertreatment system durability and/or
drain interval. CJ-4 oils are especially effective at sustaining emission control system durability where particulate filters
and other advanced aftertreatment systems are used. Optimum protection is provided for control of catalyst poisoning,
particulate filter blocking, engine wear, piston deposits, low- and high-temperature stability, soot handling properties,
oxidative thickening, foaming, and viscosity loss due to shear. API CJ-4 oils exceed the performance criteria of API CI-4
with CI-4 PLUS, CI-4, CH-4, CG-4 and CF-4 and can effectively lubricate engines calling for those API Service Categories.
When using CJ-4 oil with higher than 15 ppm sulfur fuel, consult the engine manufacturer for service interval.
CI-4 
Current
Introduced in 2002. For high-speed, four-stroke engines designed to meet 2004 exhaust emission standards implemented in 2002. CI-4 oils are formulated to sustain engine durability where exhaust gas recirculation (EGR) is used and are intended for use with diesel fuels ranging in sulfur content up to 0.5% weight. Can be used in place of CD, CE, CF-4, CG-4, and CH-4 oils. Some CI-4 oils may also qualify for the CI-4 PLUS designation.
CH-4
Current
Introduced in 1998. For high-speed, four-stroke engines designed to meet 1998 exhaust emission standards. CH-4 oils are specifically compounded for use with diesel fuels ranging in sulfur content up to 0.5% weight. Can be used in place of CD, CE, CF-4, and CG-4 oils.
CG-4
Obsolete
Introduced in 1995. For severe duty, high-speed, four-stroke engines using fuel with less than 0.5% weight sulfur. CG-4 oils are required for engines meeting 1994 emission standards. Can be used in place of CD, CE,and CF-4 oils.
CF-4
Obsolete
Introduced in 1990. For high-speed, four-stroke, naturally aspirated and turbocharged engines. Can be used
in place of CD and CE oils.
CF-2
Obsolete
OBSOLETE: Introduced in 1994. For severe duty, two-stroke-cycle engines. Can be used in place of CD-II oils.
CF
Obsolete
OBSOLETE: Introduced in 1994. For off-road, indirect-injected and other diesel engines including those using fuel with over 0.5% weight sulfur. Can be used in place of CD oils.
CE
Obsolete
CAUTION: Not suitable for use in most diesel-powered automotive engines built after 1994.
CD-II
Obsolete
CAUTION: Not suitable for use in most diesel-powered automotive engines built after 1994.
CD
Obsolete
CAUTION: Not suitable for use in most diesel-powered automotive engines built after 1994.
CC
Obsolete
CAUTION: Not suitable for use in most diesel-powered engines built after 1990.
CB
Obsolete
CAUTION: Not suitable for use in most diesel-powered engines built after 1961.​

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Wesmond is a premium quality lubricant crafted through 20 years of experience in the lubricant industry. Through comprehensive refinement with the latest additive technology, Wesmond has produced the best possible engine oil in Malaysia for all vehicle types.

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