Lubricants industry body the Verification of Lubricant Specifications (VLS) has issued an update on a market-wide investigation that began in 2025.
The body began looking at engine oils making claims against the Stellantis FPW 9.55535/03 specification last year. This is mandated for a broad range of modern Stellantis vehicles, particularly those with DV5R, DW10F and DW12RU diesel engines, as well as 1.2L PureTech (EB2) petrol engines. It applies to many Peugeot, Citroën, DS, Fiat, Vauxhall, Opel and Jeep models of passenger and light commercial vehicles.
The specification is designed specifically for engines with “wet belts” to prevent premature wear, degradation, and the formation of debris that can clog oil strainers.
It was introduced by Stellantis in 2023/2024 as a mandatory requirement for many vehicles to address reliability issues with wet timing belt systems, as well as engines fitted with external dry belts. Problems can arise if service intervals are not adhered to.
Running an engine with a wet belt on the wrong engine oil can cause damage and runs the risk of premature wear. Therefore, ensuring the lubricant is the specification required is crucial.
Two versions released
VLS highlights that two versions of the Stellantis FPW 9.55535/03 specification have been released so far. In July 2023, Version 1 of the specification was issued, and four engine oils were approved against it from TotalEnergies, BP/Castrol, ExxonMobil, and Stellantis’s own range of original engine oils.
In June 2024, Version 2 of the specification was released. Oils making claims against Version 1 have until June 2026 to be reapproved.
At present, the marketplace contains oils claiming compliance with Version 1, while those already approved or meeting Version 1 requirements are undergoing a series of engine tests to demonstrate suitability for approval against Version 2. This approval process is expected to conclude before June 2026. Version 2 includes four additional engine simulation tests compared with Version 1.
VLS understands that market general technology to meet Version 2 is being developed so that end users will have a choice of products that are either approved or meet the requirements of Version 2 when Version 1 is withdrawn in June 2026. There is, therefore, some overlap between oils making claims against Version 1 while simultaneously being submitted for testing against Version 2.
Oils under investigation by VLS
To verify products currently making marketing claims against this specification, VLS opened investigations into 12 engine oils. Responses from the lubricant marketers involved have included updates on progress toward passing the Version 2 engine tests. This has prompted VLS to examine these marketing claims more thoroughly than might otherwise be the case.
Nine of the 12 cases have been closed, and three remain outstanding. VLS has found the majority of claims to be valid, consisting of either rebranded approved products or oils based on the same technology as the four approved formulations. In case VLS 010236, when challenged about the evidence supporting the specification, the lubricant marketer chose to withdraw the claim. The remaining cases are expected to be closed within the next four weeks, and details will be published on the VLS website.
If you have any concerns about a lubricant, you can report them to VLS by calling 01442 875922 or emailing admin@ukla-vls.org.uk.
