I had a rodent start a nest in that area after the car had been parked for several months. It actually started a small fire on the test drive when I was selling the car. If it smells like oil smoke, the VCG and cam caps are pretty easy to replace. The CCT seal is a bit tougher and the CCT plastic shoes are more difficult, but the CCT seal and shoes requires the valve cover to be removed, so if you can't do them, leave it all for a mechanic.