What causes an oil smell in the cab of a Buick Regal?

An oil smell in the cab of a Buick Regal can be caused by several factors, including an oil leak from the engine that allows oil to drip onto hot components, producing fumes that enter the cabin. A failing valve cover gasket or oil pan gasket could be the source of the leak. Additionally, a clogged cabin air filter might not effectively filter out odors, allowing the smell to permeate the interior. It’s advisable to have the vehicle inspected by a mechanic to identify and address the source of the smell.