My nikon refurbished d7000 all of a sudden began to show dark spots on the photos (several) and when I took it in to a professional he said there appeared to be some kind of an oily substance on the sensor itself and I'm afraid it may be ruined. I have never sprayed anything into the camera except for the rocket-shaped air pump. Has anyone else encountered this problem?

Thanks

Yes, and it was documented extensively in this thread .

Pete

Visit my Nikonians gallery.

Thanks much. I'm checking the thread now.

Oily substance is oil from the shutter mechanism. That is the general consensus from all the posts. They are not that easy to clean off, but several cleanings with eclipse fluid did the trick.

Here is the site I used:
http://www.cleaningdigitalcameras.com/methods.html

If is one time issue, give it to somebody to clean. If is a recurring problem, then consider learning how to clean it yourself.

>If is one time issue, give it to somebody to clean. If is a
>recurring problem, then consider learning how to clean it
>yourself.

If it recurs then send it back to Nikon. They will fix it under warranty and likely even a bit after as it is a known issue of their making - an oil seal on the mirror drive. I had mine fixed and that was the end of the issue.