Cooling Water Consumption
 

I have a 2000 Cherokee Sport with the 4.0L inline six engine. Everything on this car looks and runs perfectly, except there's a slow but constant cooling water consumption that necessitates adding some water-antifreeze solution about once a week to the radiator overflow tank. One Jeep dealer told me that in late 1999 Jeep lightened up the head casting such that a tiny little crack develops in the head of '99-'01 Cherokees which causes cooling water to leak into an exhaust port where it vaporizes such that there's no visible evidence of a leak. Does anyone know if this is true, and what's the best way for me to rectify the problem? Thanks for any information you can give me.

Yes the 99+ heads have a potential for cracks due to casting problems. Solutions are you can wait for the crack or you can try some radiator stop leak or best case scenario is you preemptively change the head for a 96-98 head or even an aftermarket head.

Using Coolant
 

This used to happen in Heavy mobile equipment I used to work on. I used the silver powder radiator stop leak in the round tube container. it almost always stopped the coolant comsumsion. Good luck