I have a 2000 323CiC (convertible) with 91K miles. Recently I have detected an odor in the passenger cabin during idle (while the car is standing still). No smell while the car is moving. The smell is more like that of the hot engine compartment rather than exhaust. The rubber seals around the hood and cabin air inlet seem OK. Any suggestions what to look for?
Check for leaking from your valve cover gasket. Good place to look is left side of engine (looking at it from the front) right above the exhaust manifold. Chances are oil is dripping onto the exhaust manifold (it'll look somewhat wet..you'll see) and vaporizing an that's the smell you're getting but when you're diving the air is carrying that smell away. It's a pretty easy fix. Can be done in an afternoon and I think the new gasket goes for about $25. It won't hurt to have some RTV on hand to help the new gasket seal up a little better.
When purchasing a valve cover gasket - recommend getting the kit (valve cover gasket, sparkplug well gaskets, bolt grommets, etc.) - think the kit is about $65. Use caution when removing - the valve cover is plastic and you don't want to break it (about $300). Gently pry up and work around edges. Also use caution when removing the old gasket pieces - they are often brittle and you don't want pieces to go into your engine (put plastic around head to prevent pieces dropping into oil channels). When putting on new gasket, use sealant (like ultra black) ONLY on specified areas - i.e., where the VANOs unit is bolted to the head and on corners where the head is milled out in half-moons for the camshafts (the Bentley book shows areas). Too much sealant will also cause leaks. Don't forget, the torque on the valve cover gasket is 89 In/LBS - NOT Ft/LBs (1/4" torque wrench)... if no In/LB torque wrench, just tighten until you feel the bolt grommet seat. Lots of good DIY videos on Youtube.
Forgot to mention - if you have an AWD version, could also be a bad right front axle seal throwing lubricant onto your exhaust manifold/catalytic converter.but if no AWD, odds is its your valve cover gasket.