This will explaine the PD ref. The ACEA standards are prefixed with a 'G' for petrol engines and a 'D' or 'PD' for diesel. Coupled with this are numerous approvals by car manufacturers which many oil containers sport with pride. ACEA replaced CCMC in 1996 primarily to allow for greater read-across in test programs (eg for viscosity, viscosity modifiers and base oil). The CCMC specifications were G (1 to 5) for gasoline, D (1 to 5) or heavy duty diesel and PD1 and PD2 for passenger car diesel. ACEA though have a slightly different nomenclature they can be summarised as A for petrol, B for passenger car diesel and E for heavy duty diesel. The ACEA grades may also be followed by the year of issue which will be either '96, '98 (current) but coming soon is 2000. Full ACEA specs are: A1 Fuel Economy Petrol A2 Standard performance level A3 High performance and / or extended drain B1 Fuel Economy diesel B2 Standard performance level B3 High performance and / or extended drain B4 For direct injection passenger car diesel engines E1 Non-turbo charged light duty diesel E2 Standard performance level E3 High performance extended drain E4 Higher performance and longer extended drain E5 (1999) High performance / long drain plus American/API performances. - This is ACEAs first attempt at a global spec.