I have been hearing a rubbing noise for the last few weeks, very slight, so I didn't think anything of it. Finally got around to looking at it, and noticed the crank pulley rubbing on the cover. What could be the cause of this?

My best guess so far is either the timing belt guide is missing, or what I am hoping it isn't, a thrust washer is on its way out.

Any other options?

I will have a photo later if that helps, and may start getting into it to find out.

Thanks
Pat