Technical Yes, another oil thread!

[Herts Hillhopper]

There has been (and probably always will be!) an ongoing debate here about the right oils to use, and especially for the TwinAir.

In the dim and distant past, Fiat owned an oil brand, FL (Fiat Lubricants), who sold oils under the Selenia label. More recently, that brand name was bought by Petronas, the Malaysian State oil company famous for its F1 sponsorships, (and, it seems from here, https://www.lubesngreases.com/lubereport/7_40/petronas-acquires-italys-fl-selenia/ the base product in Selenia oil changed). A key thing that is supposed to make a difference (I'm not an oil expert so can't quantify this) is, in addition to being the right viscosity (the 0W30 number), Fiat want an 'ACEA C2' classification (an oil spec for lubricants that are good for engines with catalysts or diesel particle filters), and then, a very specific Fiat spec on top of that. For the Twin Air, that means the oil needs to be marked 0W30, ACEA C2, and Fiat spec 9.55535GS1. And for the MultiJet diesel in Euro 6 guise, same numbers but the last bit ends DS1 (for Diesel, as opposed to the GS for Gasoline).

So, I note with interest (while looking to see where I can by a small amount of oil locally to top up my 4x4 Euro 6 MJ, where the level has dropped for the first time since I've had it): Castrol have now released a version of their Magnetec Oil that is labelled 0W30, C2, and which meets meets both Fiat specs 9.55595GS1 and DS1 in the same oil and can be used on both petrol and diesel cars. Better still, it is (according to Halfords own website) the least expensive Castrol Oil they sell! Does that actually mean it's a 'simpler' oil than the more expensive offerings?

Take a look... https://www.halfords.com/search?q=Castrol 0w&srule=price_increase_rule

 

[jrkitching]

I'll try to summarise what I think is the collective wisdom of this forum into one post.

The 1.2 isn't critical as far as oil specs are concerned; you'd likely have to run it for an extended period with no oil in it at all to do significant harm (although that has been done!). The core engine was originally developed to run on a 10W40 semi, and the later migration to thinner and more costly full synthetics is likely all about emissions and economy. Providing there's enough in there, and you change it reasonably regularly, you'd be extremely unfortunate if the engine didn't outlast the rest of the car.

The TA is a different kettle of fish altogether. What's important with these engines is the way the oil viscosity changes with temperature; there is an accurate temperature sensor in the oil circuit, and the software converts this temperature into an assumed viscosity for the oil, and sequences valve operation accordingly. If the actual viscosity of the oil that's in the engine isn't the same as the value that's calculated from the measured temperature, the valves won't work properly. So the question you need to ask is whether the oil you're proposing to service it with has the same temperature/viscosity curve as the one that's programmed into the car's software. Do all 0W30 C2 oils have the same temperature/viscosity curve? Who knows? I've seen reports of comparative tests between different brands of the same headline oil spec which show significant variations in a number of different parameters.

Most folks reckon that the car is programmed to the specific characteristics of the Selenia oil recommended by the manufacturer, and that using the exact same oil removes one of the variables. And given that the TA's uniair actuator is a known weak point, and a £1000+ repair, it'd be false economy to save a few pounds by cutting corners on the oil.

There have been quite a number of posts from TA owners who've encountered rough running issues after servicing with other brands of oil, and who've found the problems went away after draining and refilling with the correct grade of Selenia. And there have been other posts from folks who've used other oils and reported good results.

If you've got a diesel 500, the weakest link in that engine is the camchain. Regular servicing with the best quality oil you can find will help mitigate the risk of chain failure.

 

[lunchbeers]

Coming from the Alfa stable, lots of faith has been put into the Selenia brand. I used it in my 159 once and it ate it in no time, a change and switching to Fuchs and it was fine.

My Twinair arrived with me having just been serviced with Eurocarparts' QX brand and never an issue in almost 5,000 miles

I serviced and switched to Millers and it was just as good until the day I sold it.

 

[TTR]

Eh up All

My “ten peneth” - having had my TA and serviced it myself from year 2 as the Main Stealer was useless !!!!!!

I service mine every 12 month regardless of mileage

I started with Fiat Petronas oil, then could not get it so moved to Selina as next best option at the time. Ran it up until this year on Selina then really struggled to find that so moved to Miller’s after triple checking specs.

I’ve used Millers products ( diff/ transfer / ATF ) for years on other cars, so far engine has been sound and runs sweet.

I did try Castrol latest offering a month ago when I was doing my water pump, but engine did not sound/feel right so I dropped the oil and replaced with my usual Millers , ran lovely again in minutes.

Agree this car is hyper sensative to its oil,spec and I firmly believe the uniair module needs TLC

Just my experience and opinion

HTH

 

[jrkitching]

Agree this car is hyper sensative to its oil

And the great thing about this thread is that the collective experience of what works, and what doesn't, will help folks make an informed choice.

 

[Vic20]

Would 100% back up jrkitchings words on the Twinair from experience over 10 years of this engine's ownership learning the hard way. Serviced with Castrol oil once, car started and ran fine afterwards (engine body was still warm). The next morning, the car started and ran rough as hell, driving off, it got worse and stalled at traffic lights with engine management light on. Eventually it settled down.

In un-extreme cases, the effect on the Uniair unit was more subtle but can even make the car difficult to pass MOT emissions tests.

Thanks to this great place, I learned the qualified reason for all these easily avoidable 'nightmares'!