Explanations of ACEA oil classes

ACEA - European Automobile Manufacturers' Association (French: Association des Constructeurs Européens d'Automobiles) is the main lobbying and standards group for the European Union's automotive industry. Its members include: [1] BMW, DAF, Daimler AG, Fiat Chrysler Automobiles, Ford Europe, Ferrari, Honda, Hyundai Europe, Iveco, Jaguar Land Rover, Opel Group, PSA Peugeot Citroën, Renault, Toyota Europe, Volkswagen Group, Volvo Cars and Volvo Group.

One of the major areas of ACEA's work has been the classification of 4-stroke engine oil performance classes,
which defines the ACEA specifications for engine oils. The classes are usually updated every few years to reflect the latest developments in engine and lubricant technology. ACEA does not approve oils themselves, they set standards and oil manufacturers can make performance claims for their products if they meet the relevant requirements.

ACEA oil classes:
A/B: A gasoline and B diesel engine oils with high SAPS levels (SAPS - the amount of sulfated ash, phosphorus and sulfur in the oil).

The ACEA A1/B1 category has been removed with the ACEA 2016 oil sequences. From ACEA 2012: Stable high-quality oil intended for use in gasoline engines with extended drain intervals and diesel engines of passenger cars and vans, specifically designed for the use of low-friction low-viscosity oils with a high temperature / high shear viscosity of 2.6 mPa * s for xW / 20 and 2.9 to 3.5 mPa.s for all other viscosity grades. These oils are not suitable for use in some engines. If in doubt, consult the operating instructions or manual.
A1/B1 oils are primarily suitable for Ford vehicles, but they have also been used in some Volvo and Jaguar/Land Rover engines.

A2/B2 is an older oil classification that was intended for conventional petrol and diesel engines without special requirements.It was previously used in many European vehicles—such as Volkswagen, Peugeot, Opel, Renault, and others—but today it has been replaced by newer classifications like A3/B3 or A3/B4.

ACEA A3/B3 stable, class-retaining engine oil intended for use in passenger cars and minibuses in gasoline and diesel engines and/or for extended oil change intervals as specified by the engine manufacturer and/or for year-round use with low viscosity oils and/or for use in severe operating conditions as specified by the engine manufacturer.

ACEA A3/B4 stable, class-maintaining engine oil designed for use in passenger car and light truck gasoline and diesel engines, but also suitable for applications described in section A3/B3.

ACEA A5/B5 stable, class-maintaining engine oil designed for extended drain passenger car and light truck gasoline and diesel engines designed for use with low viscosity oils with an HTHS viscosity of 2.9-3.5 mPa * s. These oils are not suitable for use in certain engines - if in doubt, consult the vehicle OEM's instructions/manual.

C: Catalyst Compatible Oils
Note: These oils will extend the life of the DPF (Diesel Particulate Filter) / GPF (Gasoline Particulate Filter) and TWC Three Way Catalyst (Gasoline Engine Three Way Catalyst) and maintain the vehicle's fuel economy.
Warning: Some of these categories may not be suitable for certain engine types - if in doubt, consult the vehicle's OEM manual/handbook.

ACEA C class oils are not interchangeable, depending on the specific application. e.g. ACEA C1 engine oil cannot be used if the manufacturer has specified ACEA C3 oil, as C1 has a lower sulfated ash requirement than C3 oil.

Similarly, ACEA C3 engine oil cannot be used if ACEA C1 is required, as this may cause problems with aftertreatment systems such as DPFs or catalytic converters.

ACEA C1 Stable Low SAPS - low-SAPS or low-ash (oil containing minimal amounts of sulphated ash, phosphorus and sulphur) -level engine oil, intended for use as a catalyst compatible oil with extended oil drain intervals in all types of modern exhaust aftertreatment systems and high-performance passenger cars and light commercial vehicles gasoline and diesel engines designed for use with low-viscosity oils with a minimum HTHS viscosity of 2.9 mPa * s.
C1 oils are designed for diesel engines equipped with a diesel particulate filter (DPF).
C1 oils have a low ash content and are fuel-efficient, which means they are thinner, typically with viscosities such as 0W-30 or 5W-30.
They are mainly used in Mazda, Ford, and Jaguar/Land Rover engines that specifically require C1-class oil.

Oil Purchase Note:
C1 oil is generally known to be suitable for diesel engines equipped with diesel particulate filters (DPF). These oils extend the life of diesel particulate filters and provide fuel economy.
Warning: These oils have the lowest SAPS limits and may not be suitable for use in some engines. If you are not sure whether your car has a DPF filter or if you have any doubts whether low SAPS is suitable for your engine, always refer to your car's owner's manual.

ACEA C2 stable, mid-SAPS engine oil intended for use as a catalyst compatible oil at extended oil drain intervals for all types of modern exhaust aftertreatment systems and high-performance passenger cars and vans for gasoline and diesel engines. Engines designed for use with low-viscosity oils with a minimum HTHS viscosity of 2.9 mPa * s.
Suitable for both petrol and diesel engines equipped with a DPF or catalytic converter. Provides good fuel economy and engine protection.
Typically 0W-30 / 5W-30.

Oil Purchase Note:
Generally known as C2 engine oil, it is suitable for diesel engines equipped with diesel particulate filters (DPF), this specification is very similar to ACEA C1, but the SAPS limit is slightly higher. ACEA C2 is intended for high-performance diesel engines that require low-friction, low-viscosity oil.

ACEA C3

ACEA C3 is a stable, mid-SAPS engine oil designed for use as a catalyst-compatible oil with extended oil change intervals in vehicles equipped with all types of modern exhaust after-treatment systems.It is intended for high-performance passenger car and light commercial vehicle petrol and diesel engines that are designed to use oils with a minimum HTHS viscosity of 3.5 mPa·s.

Oil Purchase Note:
C3 engine oil is generally known to be suitable for diesel engines equipped with diesel particulate filters (DPF). Very similar to C2, but without the fuel economy requirements. Often meets the specifications of BMW and DaimlerChrysler diesel cars. ACEA C3 oils may not be suitable for use in some engines.

ACEA C4 Low SAPS stable full-range engine oil intended for use as a catalyst compatible oil with extended oil drain intervals in vehicles with all types of modern exhaust aftertreatment systems and high-performance passenger car and light truck gasoline and diesel engines designed for use with oils with a minimum HTHS viscosity of 3.5 mPa * s.
Mainly used in Renault engines that require the RN0720 specification.

Oil Purchase Note:
C4 oil is generally known as the highest grade diesel engine oil specification for vehicles with diesel particulate filters (DPF) and gasoline three-way catalytic converters (TWC). Oils meeting this specification provide longer life for DPFs and TWCs and provide fuel economy benefits.

ACEA C5 stable, mid-SAPS, engine oil providing even better fuel economy, for use as a catalyst compatible oil at extended oil drain intervals in vehicles with all types of modern exhaust aftertreatment systems and in high-performance passenger cars and light duty vehicles. Gasoline and diesel engines designed for use and approved by OEMs for the use of low-viscosity oils with a minimum HTHS viscosity of 2.6 mPa * s.

C5 is a low-ash (Low SAPS) and highly fuel-efficient oil, suitable for both petrol and diesel engines equipped with a DPF or catalytic converter.
It is mainly used in newer engines (e.g. Volvo, Jaguar, Land Rover, Toyota) that require a thinner oil and low friction.
It is also suitable for newer Citroën and Peugeot engines (PSA B71 2312) with a DPF or catalytic converter.

ACEA C6 (from 2022) stable, mid-SAPS engine oil, providing even better fuel economy, for use as a catalyst-compatible oil at extended oil change intervals in vehicles with all types of modern exhaust aftertreatment systems and in high-performance passenger cars and light vehicles. Gasoline and diesel engines designed for use and approved by OEMs for the use of low-viscosity oils with a minimum HTHS viscosity of 2.6 mPa * s.
ACEA C6 is suitable for petrol and diesel engines equipped with a DPF or catalytic converter. It provides strong protection and is also suitable for engines that require a lower-viscosity oil meeting ACEA C5, PSA B71 2010, Ford M2C952-A1, or MB 229.71 specifications.
C6 is a very common choice for modern engines, especially in Ford, Mercedes-Benz, Jaguar/Land Rover, Toyota, and Peugeot/Citroën vehicles equipped with a DPF or GPF filter.


Oil Purchase Note:
ACEA C5 and C6 engine oils are suitable for diesel engines that require a C5 specification. These oils are 0w-20 or 5w-20 engine oils. The fuel-efficient C5 claims 2% better fuel economy than C3.
 

What is the ACEA E specification and what does it mean for heavy-duty engines?

The ACEA E specification refers to engine oils specifically designed for heavy-duty vehicles, such as trucks, buses, and construction or industrial machinery. These oils are intended for diesel engines operating under high loads, high temperatures, and extended service intervals.
The ACEA designation comes from the European Automobile Manufacturers’ Association, which defines standards for both passenger car and heavy-duty engine oils.

Unlike the A-, B-, and C-series oils intended for passenger cars, the E-series focuses on durability, lubrication performance, and maintaining engine cleanliness even under the most demanding operating conditions.

ACEA E4 – High performance and long drain intervals

ACEA E4 is intended for engines without a diesel particulate filter (DPF) that require high-ash (High SAPS) oil. This type of oil supports long service intervals and provides strong protection against wear and deposits. It is commonly used in long-haul trucks and heavy industrial machinery.

ACEA E6 – Low-ash oil for DPF-equipped enginesACEA E6 corresponds to Low SAPS oils designed for diesel engines equipped with a DPF or other exhaust after-treatment systems. These oils help reduce filter clogging and maintain engine cleanliness while meeting EURO IV, V, and VI emission standards.

ACEA E7 – Reliable protection for older and newer engines
ACEA E7 is a versatile choice suitable for both older and newer diesel engines without DPFs. It provides good protection against soot, oxidation, and corrosion, making it a reliable option for mixed vehicle fleets.

ACEA E9 – Next-generation low-ash oils
ACEA E9 is designed for modern EURO V and EURO VI diesel engines. It is a Low SAPS oil that ensures long life for DPF filters and EGR/SCR systems, while also protecting the engine against wear and deposits. It is currently one of the most widely used heavy-duty oil classes in Europe.

Summary

The ACEA E series defines the quality and suitability standards for heavy-duty engine oils. Choosing the correct class depends on the engine design, emission requirements, and the manufacturer’s recommendations.
Using an oil with the wrong specification can lead to engine damage or exhaust after-treatment system failures, so it is always important to verify which ACEA E class your truck or machine requires.

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