What is it with the water industry and Mopars and Jeeps, lolol? I would try the cover first after getting the balancer off. Going to be a lot of soaking and frustration with the galvanic exchange on that one bolt. Probably going to have some more bolt heads do the same. If any break off, die grind or dremel the center of the bolt with a conical stone for a starting and CAREFULLY (as in dead straight on) drill it out with a 1/4 left hand drill bit. A good chance that if you go through the threaded end of the bolt dead center it will relax enough to break free once the drill bit snags the end. Preheating the part of the block with oxy-acetylene where it threads in and spraying the crap out of it around the threads will help a lot too. If drill doesn’t back them out, Rigid Tool makes a set of straight spline deep hole extractors. I recommend a set because if it breaks below the surface of the cover (like next to the threads) they come with drill guides that go in the bolt hole so you drill a pilot/extractor hole dead on center. One of the best things I ever got off a strap-on truck.
