Started getting a strange, intermittent "burning smell" when at stoplights, but by the time I got to destination and opened hood, it would dissipate and I couldn't locate source. Didn't smell like smoking oil, and instead smelled almost like diesel exhaust. No obvious leaks besides the residue from past leaking. Then one day I got to work and the smell was really strong, like I was right behind a badly tuned diesel puffing soot at me. Opened the hood with engine running and was greeted by the signs of oil pouring from under distributor, along with puffs of crankcase vapor, which explained the hot oil smell. In the minute I ran the car before shutting down, it left a puddle about 10 inches in diameter on the road. I already had replaced a weeping rear cam seal on the exhaust side around a year ago, so I was 99% sure I had a major failure at the intake side cam seal now. I ordered parts for quick delivery without tearing into it first, and thankfully I got it right. The old seal completely fell out when I took distributor rotor off. I replaced seal and checked PCV system, which seems to be functioning normally. The old seal just decided it wanted to walk off one day with no other signs of excessive crankcase pressure or abnormal blowby. Somehow in all of this, I'd only lost half a quart of oil, though maybe as little as a cup or two since I haven't added any oil for at least 1500 miles. Even so, this is the closest I've come to needing my oil pressure gauge to warn me the sump's going dry before I fry my engine on the freeway.