Editing Oil Labelling Explained (section)

===DIESEL===
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|CD
|Introduced 1955, international standard for turbo diesel engine oils for many years, uses single cylinder test engine only
|-
|CE
|Introduced 1984, improved control of oil consumption, oil thickening, piston deposits and wear, uses additional multi cylinder test engines
|-
|CF4
|Introduced 1990, further improvements in control of oil consumption and piston deposits, uses low emission test engine
|-
|CF
|Introduced 1994, modernised version of CD, reverts to single cylinder low emission test engine. Intended for certain indirect injection engines
|-
|CF2
|Introduced 1994, defines effective control of cylinder deposits and ring face scuffing, intended for 2 stroke diesel engines
|-
|CG4
|Introduced 1994, development of CF4 giving improved control of piston deposits, wear, oxidation stability and soot entrainment. Uses low sulphur diesel fuel in engine tests
|-
|CH4
|Introduced 1998, development of CG4, giving further improvements in control of soot related wear and piston deposits, uses more comprehensive engine test program to include low and high sulphur fuels
|-
|CI4
|Introduced 2002, developed to meet 2004 emission standards, may be used where EGR ( exhaust gas recirculation ) systems are fitted and with fuel containing up to 0.5 % sulphur. May be used where API CD, CE, CF4, CG4 and CH4 oils are specified.
|}


Note:
All specifications prior to CH4 are now obsolete and although suitable for some older vehicles are more than 10 years old and do not provide the same level of performance or protection as the more up to date CH4 & CI4 specifications. 

If you want a better more up to date oil specification then look for SL, SM, CH4, CI4