It's frustrating when you're trying to remove a bolt and it snapped completely. No need to worry, you can remove it in about 10 minutes with a welder. You can try to drill a hole in the broken bolt and try to use a screw abstractor to get it out but it is easier said than done. Sometimes, you can get a drill in the tight space. Drilling a straight hole is even harder. One slip can mess up your engine block. Watch this video, try this method.