Our 2001 XJ had the radiator replaced in the last year or two. The last time I removed the radiator cap (engine cold), I noticed the coolant right there beneath the cap was a brownish/grayish color. Something must be wrong. I was going to add some radiator flush to the system, but now I'm thinking I better look into things a little more deeply (maybe start with a compression check). Odometer reads about 195,000 miles now.

 

Update: We tried to drive it 10 miles to storage but only made it 5 miles before all the coolant leaked out in an area under the passenger side upper radiator hose. The hose itself is dry, looks like the leak is located somewhere below the hose.

 

Might want to stick to the other thread you started on this