Can you use oil base paint primer over wallpaper then paint a color on

Yes you can. Here's a little tip list

http://www2.benjaminmoore.com/en-ca/for-your-home/painting-over-wallpaper

No - don't paint over wall paper. You will just make it really hard to get it off one day. Eventually it will look bad and have to come down.

I would try to take the wallpaper down first, then prime and paint. I know it takes a while and some patience to do this, but you will be happy in the end. In my previous home they painted over the wallpaper and all I could see was light grey fruits and flowers. I really didn't notice at first, but once I moved in I did. I just wallpapered over the painted wallpaper, if that makes sense. because that was the cheapest way to go. When I went to sell the house I had all the wallpaper removed the walls redone and painted. It was expensive.

You can paint wallpaper with a waterbased blocking primer then paint. Or use primer and paint combo and just give it extra coats until any pattern or color is covered. Be sure all wallpaper edges and seams are securely pasted. Good luck

If you are going to paint over the wallpaper or any wall. You should wash down with STP cleaner first , this will remove any grease or dirt,that way the paint will adhere better.

You can prime and paint. But I wouldn't. Always the chance of the wallpaper bubbling or peeling from he moisture in the paint. Would be hard to remove in the future as Lisa says. Seams could start to separate down the line.

Dp not paint over wallpaper, down the road it will bubble and peel, save yourself the headache and remove it