What Causes the Smell of Engine Oil from the Air Conditioning?

[BarrettAnn]

There are several reasons why the air conditioning might emit a smell of engine oil: 1. Exhaust from the vehicle in front: When using the air conditioning in external circulation mode, the exhaust from the vehicle ahead might be mistaken for the smell of engine oil. Of course, it's also possible that the vehicle in front has an issue causing its exhaust to contain oil components. In this case, you can switch to internal circulation mode and check if the smell persists. 2. Dirty air conditioning system: For instance, oil might have adhered to the air conditioning ducts or the air filter. Therefore, it's necessary to replace the air filter and clean the air conditioning system. 3. Negligence during maintenance: For example, if the engine oil cap wasn't properly secured after an oil change, or if too much transmission fluid was added, causing it to be expelled from the vent hole. 4. Oil leakage: Key areas to inspect for leaks include the valve cover gasket, rear crankshaft oil seal, and the oil pan drain plug.