Valve Cover Leaking?

[Quadzilla724]

While driving my 03 Trailblazer EXT 4.2L I smelled a strong odor of burning oil. Upon looking under the hood, it appears oil is seeping from under the valve cover and dripping on the hot parts. I had my oil changed about a month ago and it's still topped off. The oil color seems fine too. There is no Check-Engine light and all the gauges are were they're supposed to be. The vehicle seems to be running just fine and I'm not noticing any drips on the ground when I park. My questions are, is this most certainly a bad gasket or should I look into other possibilities. Also, is it safe to continue driving it until the weather gets warmer to attempt to change this myself. Right now it's 5° out and my garage is too small and dim to try to work on it. I plan to check the oil level regularly if that's the case. Thanks for any input!

Again, the only symptom is an occasional smell of burning oil while driving and then the lingering odor after I park and walk away from the truck after my trip.

[Quadzilla724]

A couple if other things I've noticed: It only seems to leak when the truck is started and driven in very cold temps (10° and below). When garaged, it doesn't seem to leak when driven. Also, there is a yellow sludge under the oil cap. The dipstick shows full oil and the radiator is still topped off.

Still the gauges are all where they're supposed to be when driven; there's no CE light and performance seems fine.

Any ideas what to check are appreciated.

[Quadzilla724]

Let me ask you this...if the coolant level remains topped, is it safe to rule out head-gasket blowout?....

[Loverotties]

No,just that it's not blown out by where the a water runs.