API, ACEA and manufacturer approvals: how to read an oil label
Viscosity describes how the oil flows; the specification describes what tests it passed: deposits, wear, fuel economy, compatibility with catalytic converters and particulate filters. For a modern engine the specification matters more than the brand.
API: the American system
Petrol-engine categories start with S. The main current one is SP, introduced in 2020; SQ was added in 2025. Each new category includes the requirements of the ones before it, so an SP oil can be used where SN is specified. SP added protection against low-speed pre-ignition (LSPI) in direct-injection turbo engines and against timing-chain wear.
Diesel categories start with C. A label such as “API SP/CF” means the oil suits petrol engines and older diesels without a particulate filter.
Next to API you will often see ILSAC GF-6A, the standard for fuel-economy oils used by Japanese, Korean and American engines. Its sibling GF-6B covers only 0W-16 and does not replace GF-6A.
ACEA: the European classes
ACEA groups oils by purpose. The main thing is to tell full-ash A/B oils from low-ash C oils.
| Class | For which engines | HTHS, mPa·s |
|---|---|---|
| A3/B4 | Petrol and diesel without a particulate filter, high loads | 3.5 or more |
| A5/B5, A7/B7 | Engines designed for fuel-economy oils | 2.9–3.5 |
| C2 | With a particulate filter or catalyst, fuel economy | 2.9 or more |
| C3 | With a particulate filter, high loads | 3.5 or more |
| C5, C6 | Recent fuel-efficient engines with filters | 2.6 or more |
Cars with a diesel particulate filter (DPF) or a petrol particulate filter (GPF) need low-ash oil: ash from the additives in regular oil slowly clogs the filter. The reverse also holds: low-HTHS oils such as A5/B5 or C5 must not go into an engine that doesn’t allow them.
Manufacturer approvals come first
Carmakers add their own tests to the general standards and list them in the manual as approval codes: GM dexos1 Gen 3, VW 504 00/507 00, MB 229.51, BMW Longlife-04, Renault RN17 and others. If such an approval is listed, choose an oil that carries it; that is more reliable than matching API and ACEA.
Some approvals come in generations that are not interchangeable both ways. VW 508 00/509 00, for example, is a 0W-20 oil for newer engines and must not be used where 504 00/507 00 is required.
“Approved” and “meets” are not the same
Labels use two kinds of wording. “Approved” means the carmaker tested the oil and granted the approval; dexos oils, for example, carry the logo and a licence number. “Meets the requirements of” or “recommended for” is the oil maker’s own claim, without official testing by the carmaker. For a car under warranty you need the official approval.
Reading a label: an example
Take a typical line: “SAE 5W-30, API SP, ILSAC GF-6A, ACEA C3, MB 229.51, VW 504 00/507 00”. That is a 5W-30 oil that meets current API requirements for petrol engines, is low-ash under ACEA C3 and so suits cars with a particulate filter, and carries Mercedes-Benz and Volkswagen approvals.
Not sure which oil fits your car? Send us the model, year and engine size.
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