I have oil as well in the ports.

Last weekend I replaced the right-front wheel bearing in my 2007 Aveo (87k kilometers, or 54k miles) because it was "clicking" in time with the speed of rotation of the wheel. Note however that it did not make the clicking noise when the car was jacked and the wheel was free to rotate. There had to be the weight of the car on the bearing before it made the noise. That went reasonably well, given my lack of knowledge of "pressing" bearings into hubs/sleeves, etc. In the good old days, I would take the wheel off my '77 Malibu and pop off the bearings, repack them and put the same bearing back into the wheel. No issues. Today cars are different obviously.
Following the bearing project, I saw the references on this site to the possible issue with the timing belt on the Aveos and decided to replace it, along with the coolant pump and the tensioner and the guide wheel. Got the parts (the Timing Belt Kit) from Part Source (am in Canada). You know a car has an issue when you go to get a part and learn that the dealer has a whole kit to address the timing belt and related components. When I read that some guys have blown up the valves when the belt broke, I was concerned as I have two Aveos and do not want to have two valve jobs. That project is underway and going reasonably well, with the exception of that blasted water pump. It plays double duty as pump and tensioner for the belt and of course needs a special tool J-42492-A to rotate it. One can, with considerable trouble, rotate it with a pair of pliers with a 40mm end gap, but such is not easy when you need to line up the timing marks on the cam gears and the drive shaft at the same time.
To relieve the tension on the Cam pulleys, I decided to loosen the spark plugs. Of course to do so, one needs to take off the cam cover—about 24, or so, long bolts. No issue with that if you have a speed wrench, which I have. So, I thought if I go this far, why not replace the plugs. So I looked down the plug ports and saw what I thought was a small pool of water. Got the air gun out and blew it out--and in the process blew a couple of ounces of oil all over the place. Seems the plug ports were slowly being filled up with oil. Hmmm.
With the cam cover off I could see that the oil from the cam galley was getting past the gasket and into the plug ports. I have never seen plug ports so deep—they are about 6 inches deep. Once anything gets into those ports, there is only one place to go—into the combustion chamber, so if you contemplate removing the plugs, blow out the ports first with a compressor and an air gun. So, I called the dealer to see if they had a new gasket. They have several said the parts fellow and so I went to pick one up ($21). You know that when the dealer has a stock of Aveo valve/cam cover gaskets in stock, the poor cars have a chronic issue. The valve cover issue was a bit of a diversion, but I was a bit alarmed to see that all four of the ports contained a significant amount of oil. Make sure you check your ports out folks!
Back to the timing belt—I hope to get that project finished tomorrow. I have a couple of photos of the projects if you like taken on my Playbook. Let me know. Having trouble linking my BB Playbook to my Windows 8 desktop at the moment…another issue to sort out when the car is running again. Cheers.