ronbp

Well, losing water, overheating, and lots of smoke are typical of head gasket problems (even though it may not smell like it). Pull the spark plugs and inspect them, one may be obviously different looking. Do you have or can you borrow (Autozone lends tools but I don't know about one of these) a cooling system pressure tester? While the plugs are out hook up the tester, pressurize the system to @12lbs or so and let it sit overnight. In the AM turn the engine over with a wrench on the crank pulley bolt and see if water gets pushed out a plug hole. As for other odd-ball reasons for the overheating...I've seen the impeller break off a water pump....I've seen it where the lower hose to get sucked together at medium high rpms. At idle it's fine. (That's why most lower hoses have that "spring" in them.) I'm doing head gaskets on a Ford 4.0L right now...it was losing water, there would be puffs of white smoke occasionally and it would run rough when cold but it wasn't overheating or over-pressurizing the water system. But pulling the plugs and finding water in #3 cylinder sealed the diagnosis. Ron

Lots of white smoke out the tailpipe that's kind of sweet smelling? And you have to keep adding water when there is no external leak? There's a head gasket problem or a crack... IMHO. Ron