I am new user to this site, have 97 4L V6 xlt with 145k miles. Started to overheat this summer, would add coolant to radiator once a month and went on my merry way, heater would sometimes not work at all, just blowing cool air in cab, no smell in cab or presence of leak on passenger floor board. Looked for leak, found leak on connection piece of heater supply and return line.
A plastic piece, with a 'bell' shaped piece with a wire connected to it, some type of vacuum I suppose, is the culprit. Now, I've noticed the leak spots on the garage floor have moved, now it looks like there is a leak above the connection of the lower rad hose to the engine block!! The majority of the coolant seems to be under the fan pulley housing. The hose doesn't have any moisture on it and is warm when to truck is running. There is moisture in the tailpipe as well.
Have been looking all day for another source of leak, no luck yet. Have read previous posts and found some info, but would like some more ideas.