Data and methodology
Every figure on this site is traceable to a source. This page lists what those sources are, how a registration becomes an oil specification, and where the limits of the data lie.
From registration to specification
A DVLA Vehicle Enquiry Service lookup returns make, fuel type, engine capacity and year of manufacture.
Capacity and year alone are ambiguous, so an aftermarket dataset resolves the specific engine code. Where it cannot, we ask the driver to pick.
Service documentation gives the grade, approval, fill capacity and interval for that code.
Products are checked against the manufacturer's own licence register before being listed.
Sources
The official DVLA API returns make, fuel type, engine capacity, year of manufacture and tax status for any UK registration. Free to use with a registered API key, and rate limited per key.
Free government API returning MOT test history and recorded mileage, used to sanity-check the model year and to estimate annual mileage for interval advice.
A free bulk download of every car sold in the UK with engine capacity, fuel, transmission and derivative name. This is what bridges a bare capacity and year to a named derivative.
The aftermarket standard for linking a registration or VIN to a specific engine code, and for oil filter part numbers. Commercially licensed.
OEM-based maintenance data including lubricant specifications and fill capacities for the large majority of cars on UK roads. Commercially licensed per seat or per API.
The published European sequences defining the A/B, C and E classes. Freely available from ACEA and the reference for every class letter we show.
American licensing standards used for Japanese and Korean vehicles where no European approval exists. The licensee directory lists every actively licensed product.
Manufacturer-published lists of licensed oils — Mercedes-Benz BeVo, GM dexos, and the per-approval product lists from VW, BMW, Ford and PSA — used to confirm that a product genuinely holds the approval it claims.
Known limits
A registration identifies the vehicle as first registered, not as it stands today. An engine swap, a rebuild, a conversion or a factory update to a different oil specification will not show up in the lookup, which is why the service book always takes precedence over anything published here.
Where a manufacturer revises a specification mid-production, two cars of the same model year can require different oils. In those cases we show the later requirement and note the change on the specification page.
Fill capacities are with-filter figures from service documentation. They are a guide for how much oil to buy, not a target to pour to. Always finish the fill against the dipstick or the electronic level reading.
Our engine index is expanding by engine code rather than by model, because that is the unit the specification is defined against. Where a registration resolves to a vehicle we do not yet index, we say so rather than guessing.
Point us at the manufacturer documentation that contradicts it and we will check and update within a week.
Send a correction