Well, was driving the CDV back from Marathon today, trip was going well, when I began hearing a rattling coming from the engine while going up a bridge. It got steadily more pronounced under load, but went away when I would ease off the throttle. The car ran smoothly otherwise... the only symptom was the noise. I pulled over at the first service station I came across and popped the hood, and the engine was positively smoking! Oil smoke was coming out of the pvc holes, valve cover gaskets were SIZZLING with smoke coming out of there, and the car seemed to be positively cooking. I went back and double checked my temp gauge, and it was only reading at the halfway point... no high temp reading, no temp warning light. I added another quart of oil and parked the car... plan to go back this afternoon and pick it up once it's cooled down. I was afraid I had blown the head gasket so I checked the oil before adding; although it was low, it didn't appear to have any coolant in it. Any suggestions as to what I should look for when I go back for the car?

Okay, I went back and picked up the CDV yesterday evening. Had to totally refill my radiator... the rubber hose I had used when I added the coolant resevoir had split at some point over the past few days, so I was evidently losing coolant all the way to Marathon and back. The car runs fine, no rattling or knocking, no oil in the coolant, no coolant in the oil, so I think I may have gotten lucky this go 'round. Gotta find some hose with better heat resistance, I guess. And time to hook up my new gauge pod!

It would be a good idea to change the engine oil as it may have been cooked.

...and the transmission fluid as well! On a modern car, like the Northstar powered ones it will prompt you to replace the engine and transmission if the engine overheats.
I'd change them both just to be safe! Glad you found the problem and nothing is damaged.