Oil and Coolant Consumption

[germaneighter]

2006 CS has about 22K on the odometer. I purchased it with 10.7K on the clock. I drive it daily (about 75 miles/day). I have not tracked this car yet but I do not baby it. At about 18K I noticed the oil level dropping a little more rapidly than I'd like. I also noticed coolant level was low. Coolant took about one quart to bring to the min level.

I just did my 3rd oil change (0-40 M1) a couple weeks ago and it has dropped one quart in 450 miles. Coolant level is also below min level again.

I always cut oil filter open and inspect. To date the filters have not shown anything.

Also, at around 18K I've noticed the exhaust tip was really sooty.

There is no smoke at start-up or upon hard acceleration.

Do you think an AOS could be the cause at 22K? Or do you suspect something more serious?

thanks