2001 Buick LeSabre Custom 3.8

I get this very faint burnt oil smell from my HVAC with the AC on. The vehicle must be driven for at least 2-3 minutes before it shows up. It goes away after 1-2 minutes, then after making a turn or two I can smell it again - slightly. Then it goes away again.

My guess is it'* the rear valve cover gasket - a very small drip onto the rear exh manifold. I constantly check the oil level and it'* always full. I can see no leaks or spots at the front valve cover or the top of the rear valve cover. The front exh manifold has no spots on it. I can't see the rear exh manifold from the top.

I got my first (partial) look inside the engine today as I was checking the date of my upper plenum. I had to remove the oil fill tube to get the "injector sight shield" off (gotta love that name) I could see inside the front valve cover pretty well and it looked clean as a whistle - not a spot of dirt or sludge.. only my clean Mobil 1 coating everything. I'm going to imagine the rest of the engine is that clean

A new gasket on the valve cover nearest the firewall fixed that issue on mine. It was leaking so bad you could see the smoke through the windshield.

Thanks. I haven't seen any smoke so I'll be catching it early.