* Oil leak: One possibility is that there is an oil leak somewhere in the engine. This could be caused by a cracked oil pan, a bad oil filter seal, or a damaged oil line. Check the engine for any visible signs of oil leakage, and if you find any, you should have your car repaired as soon as possible.
* Piston rings: Another possibility is that the piston rings in your engine are worn or damaged. This can cause oil to leak into the combustion chamber, where it will burn and produce smoke. You may also notice a decrease in oil pressure and an increase in fuel consumption if your piston rings are worn.
* Valve seals: Worn or damaged valve seals can also cause oil to leak into the combustion chamber. This can cause similar symptoms to worn piston rings, such as smoke, decreased oil pressure, and increased fuel consumption.
* Turbocharger: If your Passat has a turbocharger, a failed turbocharger seal can also cause oil to leak into the exhaust system. This can produce a burning oil smell, especially when the car slows down.
If you are not sure what is causing the oil smell in your Passat, you should take it to a qualified mechanic for diagnosis.
