Crankcase Ventilation Issues in Certain Vehicle Models

Oil residue around the air hose connected to the throttle body can be a sign of crankcase ventilation issues, particularly in European and Japanese engines. In modern vehicles from manufacturers such as Mercedes-Benz, BMW, Audi, Porsche, VW, Volvo, Jaguar, Lexus, Toyota, and Honda, a small amount of oil vapor is normal.

However, when it pools in the air intake hose, it may indicate a clogged or failing PCV (positive crankcase ventilation) system. This can lead to issues such as rough idling, hesitation, or a check-engine light. The problem can affect various models, including the 2010 or newer BMW 3 Series, Mercedes C-Class, Audi Q5, Toyota Camry, and Honda Accord, as well as hybrid models.

Replacing the PCV valve, cleaning the throttle body, or swapping a worn hose can often resolve the issue. If left unaddressed, it can lead to more significant problems like oil leaks or intake carbon buildup. According to industry reports, addressing crankcase ventilation issues promptly can help prevent further damage to a vehicle's engine.