The 2004 Cadillac CTS typically requires 5W-30 engine oil. It's recommended to use a high-quality synthetic or conventional oil that meets the API (American Petroleum Institute) standards. Always check the owner's manual for specific recommendations and requirements for your vehicle.
10w30
10w30 Your oil cap on the engine block will have it printed.
The 3.6 engine can take regular (89 octane)
Synthetic oil.....5W30 Mobil1 or valvoline
They take Regular or E85
They take Regular or E85
it take dexcool its a orange antifreeze that is approved by gm.
Premium Unledded fuel.
Yes, it will. Your engine will not run properly without a converter installed. It is also illegal to remove a converter and carries a $2,500 fine if you are caught.
According to the 2004 Ford Expedition Owner Guide : Both the 4.6 and the 5.4 take the ( Motorcraft FL-820-S ) engine oil filter
It will vary by location and where you get it from, however it is inexpensive, $10ish give or take.
Look on the cap, should be 10w 30