2003 Cadillac CTS White Smoke

White smoke or semi white can be produced in several ways. One way is oil this is normally a whitish blue to blue smoke and has the apparent smell of oil being burned. Next could be antifreeze when it is being burned it has a sweet type of smell and tends to dissipate in the air rather quickly. Next is automatic transmission fluid which is normally found on automatic transmissions and its normally drawn into an engine thru a vacuum line via a defective transmission modulator valve or some other defective part. Transmission fluid is very apparent and billows out so bad that you can't see anything behind you.

First try smelling your tail pipe right after you shut the engine off. If it's sweet, it's coolant. If it's burnt smell, it's oil. You could also run your finger inside the tip of the tail pipe. It'll be black, but if it's an oily residue, then it's oil. If it's shiny and clear, it's coolant.

If it's oil, first check the PCV valve for a stuck open valve. (Shake it next to your ear. If it rattles, it's GOOD, if it doesn't, it's BAD) If that checks out good, then you either have worn valve guides or piston rings.

If it's coolant, you either have a blown head or intake gasket. (Both very costly)