Fiat, FCA and now Stellantis identify engine oils with vehicle-manufacturer requirements in the 9.55535 family. These requirements combine an intended application with oil-performance and viscosity requirements; a similar viscosity grade or an ACEA sequence alone does not make one Fiat/Stellantis requirement interchangeable with another.
Always use the exact requirement, viscosity grade and service interval stated in the current owner’s handbook or service documentation for the specific engine. The same model line may use different oils by engine, emissions equipment, model year and market.
Current and later Fiat/FCA requirements found in manufacturer documentation
| Requirement | Documented application or accompanying classification |
|---|---|
FIAT 9.55535-S1 | Legacy low-SAPS requirement documented with SAE 5W-30 and ACEA C2 for certain diesel applications. |
FIAT 9.55535-S2 | Legacy requirement documented with SAE 5W-40 and ACEA C3 for selected petrol engines, including some turbocharged applications. |
FIAT 9.55535-T2 | Documented with SAE 5W-40 and ACEA C3 for certain petrol/LPG engines. |
FIAT 9.55535-GS1 | Documented with SAE 0W-30 and ACEA C2 for selected petrol engines, including some 1.4 Turbo MultiAir and plug-in-hybrid applications. |
FIAT 9.55535-DS1 | Documented with SAE 0W-30 and ACEA C2 for selected diesel engines without AdBlue. |
FIAT 9.55535-GH2 | Documented with SAE 5W-40 and ACEA C3 for particular high-output petrol engines, including the 1750 Turbo petrol application in Alfa Romeo documentation. |
FIAT 9.55535-DM1 | Documented with SAE 0W-20 and ACEA C5 for selected Euro 6d-Final petrol mild-hybrid engines and some 1.3 Multijet diesel applications with AdBlue. |
FIAT 9.55535-DSX | Documented with SAE 0W-20 and ACEA C2 for selected 1.6 Multijet diesel engines with AdBlue. |
FIAT 9.55535-GSY | Documented for a 2.0 T4 petrol application with SAE 5W-30, API SP and ILSAC GF-6. This is a distinct FCA requirement; do not substitute it with GS1 because the suffixes are similar. |
Stellantis FPW 9.55535/xx requirements
For newer Stellantis-era vehicles, harmonised requirements may be printed as Stellantis FPW 9.55535/xx. These are separate manufacturer requirements and should be matched exactly as specified by the vehicle documentation.
| Requirement | Documented viscosity and industry classification |
|---|---|
Stellantis FPW 9.55535/01 | SAE 0W-20; ACEA C6. Fiat 600 and Fiat Junior hybrid documentation permits this requirement as an alternative to PSA B71 2010. |
Stellantis FPW 9.55535/02 | SAE 0W-30; ACEA C2. Product documentation identifies backward compatibility with several earlier Fiat requirements, but that does not override a vehicle handbook that calls for a different requirement. |
Stellantis FPW 9.55535/03 | SAE 5W-30; ACEA C3 and API SN PLUS on the documented OEM product. It is not adequately identified by an ACEA C3 claim alone. |
Stellantis FPW 9.55535/09 | SAE 5W-40; ACEA C3 and API SN on the documented OEM product. |
Stellantis FPW 9.55535/10 | SAE 5W-40; ACEA A3/B4 and API SP on the documented OEM product. |
Historical 9.55535 designations
The older designations G1, G2, H2, H3, D2, M2 and N2 are retained here as historical Fiat oil qualifications encountered in older service literature and lubricant catalogues. They should be treated as legacy, engine-specific requirements rather than as current general-purpose recommendations. In particular, older references to API SM, ACEA 2004 sequences or GM-LL-B-025 describe period material and must not be read as current approvals.
Likewise, an unsuffixed reference to FIAT 9.55535 in older documentation is not enough to select an oil without confirming the engine-specific handbook requirement. Where a handbook gives both a Fiat/Stellantis requirement and an ACEA or API category, the manufacturer requirement remains the controlling identifier. See also why an ACEA sequence is not a vehicle approval.