Originally Posted By: CBR.worm
It seems to be sucked in through the PCV system. After a hard day the intake manifold is wet with oil and has puddles. Some people use catch cans for this reason.
I would tend to agree with this statement. When I pulled my intake manifold off to change my spark plugs, it did have some oil trickling out of the PCV system hose connected to the manifold. I've always used synthetic, so the manifold was very clean and had no carbon build-up anywhere. But there was a noticeable "stream" of oil in there. I've always wanted to get a catch can set-up installed, but I haven't had time to build one yet. Maybe for the next time I do the spark plugs (which should be next year I think - if my driving distances keep up).
My car has ~115,000 miles now and it's an 05. Driving is mostly high speed highway (~85-90 mph, at ~3,500 rpm). The rest is stop and go traffic. Consumption is pretty stable at 1 qt per 3,500 miles. If I do less highway, I see less consumption (almost nothing if I do all suburban/city driving, which is very rare for me now). Does not seem to vary at all with oil choice (5W30, 0W30, 5W40, 10W40, 0W40).