You can see that the overall length is about 5/8", and there's only about 3/4" space between the head of the bolt and the back of the crank shaft balancer. Once you break it loose, you can unthread it with you fingers. The bolt won't come all the way out of the hole in the oil cooler housing, but it will be completely unthreaded from the block. When putting the oil cooler housing back in, make sure you do this bolt first.
edit: fixed the pic links.