I drive a 2003 Audi A4 with a 1.8T. As the engine gets close to operating temperature, I can smell the unmistakable aroma of burning oil through the ventilation system. If I close the vents (recirculation), it's gone. The issue is that that car doesn't seem to be burning any oil, or losing any noticeable amounts. Any ideas? Mark, Toronto
Most vehicles draw fresh air into the cabin from the cowling-wiper area intake. As you have indicated, switching from fresh air to recirculate will start recycling the interior air, thus diminishing the smell. It's true, it doesn't take a significant amount of leaking oil to alert us to a problem. The vehicle in question has several areas that I can think of that might be the source. The most obvious is a leaky valve cover gasket. Additionally, there are a couple of alternative sources that are not as easy to spot.
First, there are an abundance of plastic and rubber hoses, which reside underneath the intake manifold, serving as vent tubes for the PCV system and turbo system piping. These hoses are difficult to diagnose due to their remote location, and are prone to crack and leak engine crankcase vapours.
Second, the timing chain tensioner located at the back of the motor, which encompasses an external electrical solenoid, may leak oil down the back of the cylinder head dripping onto a plastic coolant distribution flange. The continual oil leak onto the plastic flange causes the flange to become soft, adding an additional coolant leak to the already expensive repair of the timing chain tensioner.
Lou Trottier is owner-operator of All About Imports in Mississauga. Have a question about maintenance and repair? E-mail globedrive@globeandmail.com, placing "Lou's Garage" in the subject area.
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