Most oils have both petrol and diesel ratings which are labelled by their API or ACEA ratings. The ratings are as follows but at those prices, you'll be getting what you pay for.

• API = American Petroleum Institute
• S = Service – Petrol Engine Performance
• C = Commercial – Diesel Engine Performance

• SG – Introduced 1989 has much more active dispersant to combat black sludge
• SH – Introduced 1993 has same engine tests as SG, but includes phosphorus limit 0.12%, together with control of foam, volatility and shear stability
• SJ – Introduced 1996 has the same engine tests as SG/SH, but phosphorus limit 0.10% together with variation on volatility limits
• SL – Introduced 2001, all new engine tests reflective of modern engine designs meeting current emissions standards
• SM – Introduced November 2004, improved oxidation resistance, deposit protection and wear protection, also better low temperature performance over the life of the oil compared to previous categories.
• SN – Introduced in October 2010 for 2011 and older vehicles, designed to provide improved high temperature deposit protection for pistons and turbochargers, more stringent sludge control, improved fuel economy, enhanced emission control system compatibility, seal compatibility, and protection of engines operating on ethanol-containing fuels up to E85.

• 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
• CF-4 – 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
• CF-2 – Introduced 1994, defines effective control of cylinder deposits and ring face scuffing, intended for 2 stroke diesel engines
• CG-4 – 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
• CH-4 – 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 fuelsSG – Introduced 1989 has much more active dispersant to combat black sludge.
• CI-4 – 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.
• CJ-4 – Introduced in 2010 exhaust emission standards. These oils are formulated for use in all applications with diesel fuels ranging in sulphur content up to 500 ppm (0.05% by weight). However, the use if these oils with greater than 15 ppm (0.0015% by weight) sulphur fuel may impact exhaust after treatment system durability where particulate filters and other advanced after treatment 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.

ACEA (European Automobile Manufacturers Association) have a system of rating oils, which you will find on the container of almost every oil on the market. These are the current specifications, previously oils were given separate petrol and diesel ratings, but from November 2004 onwards, those have been combined (A still refers to Petrol and B to Diesel engines).

• A1/B1 – Category for Fuel Economy engine oils with especially low High Temperature High Shear viscosity. HTHS of 2.6 to 3.5 mPas applies to XW-20, 2.9 to 3.5 mPas for all others. Corresponds to the old A1 and B1 specifications with some new engine tests.
• A2/B2 – Basic requirements.Will be replaced by the GLOBAL DLD-1 specification.
• A3/B3 – Category for high-performance and Fuel Economy engine oils. Exceeds ACEA A1/B1 with regard to Noack (evaporation losses), piston cleanliness and oxidation stability.Extended oil change intervals possible.
• A3/B4 – Same as A3/B3 but also for direct injection diesel engines.
• A5/B5 – Category for high-performance engine oils. For TDI engines with Fuel Economy Performance. In addition with lowered HTHS (2.9 to 3.5). Extended oil change intervals possible.

An additional category appears in these specifications in which sulphate ash, phosphorous and sulphur content (SAPS) is limited.

• C1 – Largely based on the ACEA A5/B5. Strict limitation of SAPS content.Low HTHS viscosity of >2.9 mPas
• C2 – Same as C1 but with somewhat higher SAPS content permissible (as with C3)
• C3 – Same as C2 except for HTHS > 3.5 and without Fuel Economy performance
• C4 – Same SAPS content as C3, HTHS viscosity as C1

Cheers Simon

Edited by Xileno on 06/04/2021 at 21:22