Air guide is just the plastic under the bumper, some call it an air dam. The intercooler has a weep hole on the passenger side, and if the turbo is leaking the weep hole will let out hot oil vapors which condensate on the air guide and then the oil runs to the driver's side before dripping to the ground.

AutoRx will not fix valve stem seal leaks. A good and tight vacuum system cause more oil to creep up the valve stems and enter the intake manifold so it gets burned.

A turbo with a bad exhaust side seal will push oil into the exhaust and burn it there, creating a little blue exhaust smoke but nothing like the 700 series white cloud! But that would be enough oil to coat the O2 sensor and mess things up.
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My name is Klaus and I am a V♂lv♂holic