GM buy those diesels From Fiat Power Train.Petrol engines are based on GM units, but are not the same as those used on other GM cars.
Diesel engines are Italian.
Oops - How could I forget the 1750! 100% Italian, and the best petrol engine in the 159. (In the Engine of the Year Awards shortly after its launch, the judges noted that the marks awarded to the 1750 by those who'd driven it were so good that if more judges outside of Europe had been able to test it too, it would have most likely got the award)The TBI engine is fiat again.