If your vehicle is showing burning oil smell from the engine bay or ac vents, here are the most likely causes and the parts you'll need to fix each one.
The valve cover gasket is the most common source of oil leaks. When it degrades, oil drips directly onto the hot exhaust manifold below it, creating a strong burning smell that gets pulled into the cabin vents.
If the oil was recently changed or topped off, oil may have been spilled around the filler neck or filter housing. This residual oil burns off on the hot engine block and exhaust.
A blocked Positive Crankcase Ventilation (PCV) system builds up pressure inside the engine, forcing oil out of various seals and gaskets onto hot engine components.
Worn camshaft or crankshaft seals at the front of the engine can leak oil that gets blown backward onto the hot exhaust system while driving.
The seal between the engine and transmission can fail, allowing oil to drip down and blow back onto the hot exhaust crossover pipes under the vehicle.
On turbocharged vehicles, the oil feed and return lines are subjected to extreme heat. If they leak, oil drips directly onto the red-hot turbocharger housing.