Technical fiat 9.55535-s1

[Leroypanda]

Whats the difference between fiat 9.55535-s1 fiat 9.55535-s2 fiat 9.55535-s3 ?

 

[Goudrons]

These numbers are Fiat's techincal oil specs.
They relate to oil industry standards, but Fiat use them to specify the right oil for whatever Fiat engine you have.

Some might be Petrol or Diesel specific, that doesn't really mean the oil is, just that spec of oil is specific to that particular Fiat engine.

Fiat 9.55535-S1
Qualification for Diesel and gasoline engine, with exhaust treatment system, lubricants, granting fuel economy and extended drain. OEM recommended product is also approved to ACEA C2.

Fiat 9.55535-S2
Qualification for Diesel and gasoline engine, with exhaust treatment system, lubricants, with extended drain. OEM recommended product also meets: ACEA C3-04, MB 229.51 and API: SM/CF.

I seem to think 9.55535-S3 is ACEA C3 but petrol specific. (though as explained above, a different manufacturer might use oil made to the same standard and spec in a diesel model)

So your handbook might state you require 5W30 that meets Fiat 9.55535-S1 or 0W30 that meets Fiat 9.55535-S2 depending on what engine it is.

 

[Leroypanda]

so there isnt a lot of difference (oil wise) between s1/s2/s3?

 

[Goudrons]

Yes and no.
There are differences, but these S1, 2 and 3 numbers don't always relate directly to one of oil industy standards, they are Fiat standards.

The oil industry use various standards and oil is made to to those oil industry standards.
ACEA (European Automobile Manufacturers' Association)
SAE (Society of Automotive Engineers)
API (American Petroleum Institute)
JASO (Japanese Automotive Standards Organization)

This oil is then produced in various viscosities. (common to all standards)
0W30, 5W40, 10W40 etc

Then oil in quality. (ACEA qaulity standards below, other standards use a different code)
A – oil designed for petrol engines.
B – oil designed for diesel engines in private cars.
C – for light engines equipped with catalytic converters or particulate filters.
E – for commercial vehicles and trucks.

Then different performanes. (again ACEA standards)
Three category combinations for petrol and diesel engines: A3/B3, A3/B4, A5/B5.
Five categories for vehicles with a pollution control device: C1, C2, C3, C4, C5.
Four categories for commercial vehicles and trucks E4, E6, E7, E9.


Now Fiat might say the engine oil for a certain Fiat engine needs to be 5W40 ACEA C3.

There are probably dozens of 5W40 ACEA C3 oils on the market but not all might be suitable or have been tested, so Fiat set their standard so oil companies can make it to that and helps owners identify the right one.
So they add that it must meet one of their specs, eg 9.55535-S2.

So this 9.55535-S2 number helps to select the correct 5W40 ACEA C3 oil that Fiat wants you to use in that particular engine.

 

[Leroypanda]

Very informative, and ive used the wrong one.