Diesel engine oil of Fiat spec seems to command a high price yet GM spec Dexos2 oil is around two thirds the price for same brand and is recommended for Vauxhall/Opels with Fiat engines.
Has anyone used, or considered using Dexos2 oil?

No,
I use Castrol Edge Turbo Diesel 5W40 in my Fiat engine powered Alfa Romeo GT jtd.
www.castrol.co.uk

Yep Castrol all the way !
I know it ain't cheap I was lucky enough to go to their technical centre last year the technology and testing that goes in to their product is out of this world
Never skimp on oil that's for sure did a turbo on a 407 last week and the sump and oil filter were both clogged solid due to poor oil and poor servicing how they got away with just a turbo beats me

Thanks for the reply.
No disputing Castrol is a good quality product.
I'm not suggesting using cheap brand oil but Dexos2 approved oils appear to be significantly cheaper than Fiat approved oil from same manufacturer.
Incidentally I notice Castrol do not quote that they are Fiat spec - just suitable for fiats

Decro said:

Incidentally I notice Castrol do not quote that they are Fiat spec - just suitable for fiats

Click to expand...

It does!
Have a look again at Castrol Edge 5W40 FST Titanium....

Sorry Peter Pick-up,
I didn't check the 0w-40 because I was looking at 0w-30 for a diesel.
Having looked, Edge Titanium FST 0w-40 meets Fiat petrol spec- no mention of S1 diesel spec.
I don't know what viscosity oil your Alfa should have but my Bravo Multijet should have 0w-30.

5W40 Edge FST Titanium, is perfect for my Alfa with 150HP Fiat 1,9 turbo diesel engine.
I often drive long, high speed journeys on German, "no speedlimit" motorways....
Castrol Germany ditched the ..W30 recommendation for (Fiat) diesel engines some years ago, to thin at high temps....

Google: 0W30 ACEA C2

Knock yourself out (Castrol Edge FST 0W30, Mobil 1 ESP 0W30, Motul 8100 Eco-Clean 0W30).