Yolu have asked this question in the UK and Ireland section of Cars and Transport where the car was never sold.
Suggest yuo click the Internetional link to the left and select US and ask again
Hi as all american cars are mostly petrol or what they call gasoline.it being such an old car any oil would do as it would be a complete waste of money putting a synthetic oil in it.
only trucks use diesel in the states
I wouldnt waste money by using synthetic oil, we at the Cadillac dealership use wall oil or bulk oil. I have no idea what they use but its just conventional oil. Synthetic oil is mainly for longer intervals in between oil changes but since your more than likely to have an oil consumption issue with that Northstar, I would use regular old oil like Castrol or Pennzoil or whatever brand you like that is not a synthetic or semi syn & just change it every 3000-3500 miles
Do you want to make the Cadillac last or just sell it when all is in? I suggest quality synthetic.
Use whatever Cadillac recommends. Probably 5W-30 in winter and 10W-30 in the warm months. If you live in a warm climate, simply use 10W-30 year around. If you are worried about brand name, don't worry. Any motor oil which meets the latest API certification "SN" will work well for you.
I would say 5w30
desel
