Not quite Jeep related but related to your problem.Had a BMW had the water pump go and so changed it,first time was losing water and found the gasket had twisted when putting it back on(was a right pain due to location),then once all sealed correctly found i still had to top up due to an airlock in the system.Did you follow the correct proceedure for filling back up the coolant system?I know there is one to prevent air locks,but you would need another to say what it is as im not sure.I wasnt losing water as such but it still needed topping up.Hope that helps?