The Essential Guide To Motor Oil - Valvoline

7
What are API ratings?
The American Petroleum Institute (API)
classification system provides information
about the engine oil.
The letter “S” followed by another letter
(for example “SM”) indicates that the oil
is appropriate for petrol engines. SM oils
are superior to SL oils in many
performance criteria including enhanced
fuel efficiency whilst also meeting the
“energy conserving” classification and
enhanced emissions systems protection.
The letter “C” followed by another letter
and/or number (for example CI-4) indicates
that the oil is appropriate for diesel engines.
The second letter in both the “S” and the
“C” categories is assigned alphabetically.
Generally the further along we move in
the alphabet indicates the latest technology
and quality enhancements in motor oil.
What are ACEA ratings?
ACEA stands for the Association des Constructeurs
Europeens d’Automobiles and represents a large
group of European engine manufacturers. ACEA
has established four performance categories:
the A category for petrol engines; the B category
for passenger car diesel engines; the C category
represents catalyst compatible oils; the E category
for heavy duty diesel engines.
A Category (petrol engines)
A1 and A2 oils represent the base performance
level with A1 being used for lower viscosity fuel
efficient oils and A2 for higher viscosity oils. A3
and A5 oils are the highest performing ACEA
gasoline engine oils with the A3 being used for
the higher performance oils and A5 for the high
performance lower viscosity fuel efficient oils.
The A4 classification is reserved for a future
specification for direct injection gasoline engines.
B Category (passenger car diesel engines)
The B category is similarly divided with the
exception that the B4 classification for direct
injection passenger diesel engines has been
established and that the B5 classification combines
the performance requirements of B3 and B4 in a
lower viscosity fuel efficient oil.