It has a blown head gasket. How well does BAR's sealant work on this vehicle? Do I pour it into the coolant reservoir or the radiator? The car runs fine with no overheating, but the coolant reservoir gushes water.
It will probably work as well or as poorly as in any other vehicle. Bear in mind the Bar's Leak is a temporary band-aid at best. It may work for a year. It may work for a few days. It may not work at all, particularly for a severe leak. It might even plug up your radiator or heater core.
If you plan to keep the car a long time it would be best to do a proper repair. If you do want to try the sealer make sure to follow the directions exactly. It should be poured into the radiator. (If put in the coolant overflow tank most of it will just sit there and not circulate.)
If it has a truly blown head gasket, I would replace the gasket. Bar's is a temporary fix at best.
If it's not your DD, I'd fix it the right way. A quick Google search for the type of engine that 5.7L is says it's a pushrod engine, not a SOHC or DOHC. That will make the job a bit easier if you tear it tear down and reassemble it. You don't need to mess with the timing chain or cams, making sure the cams go back in exactly the way they were to keep the timing right.
On a pushrod engine you wouldn't be removing the cams to replace a head gasket. What you do need to do is number the pushrods (and rockers if removed) and put them all back in the same position since the parts wear into each other. Also the head should be checked for warpage and cracking.
That's what I was trying to say, he won't have to mess with getting the timing back in tune because the cams don't need taken out, I worded it awkwardly and couldn't edit it to fix it. Haha. I knew that about inspecting heads when they're off, but didn't think to include that. I guess most people probably don't know it. I've read and been told a good way to keep the cams and rockers together and organized is to put each pair in a zip-lock bag or something similar and number them with a sharpie on the bag or masking tape if you pull 'em out. A while back I thought my Ranger's head gasket was blowing from finding moisture on the oil cap and was planning on doing it with an old timer mechanic friend, but I found my PCV valve wasn't put back in by the shop who did a valve cover gasket job. Same shop that did my tranny. It went away after I put the valve back in. I learned my lesson about that place after all of that fiasco, haha.
Like Chuck said, keep your push rods and rocker arms marked for reassembly. I would pull the heads and send them to a machine shop for a magnaflux and rebuild (guides, 3 angle valve job, new seals and decked if necessary.) Might as well throw in a new set of lifters while you're at it.
