I just had one of those hoses on the rear coolant manifold rupture also, but it did so progressively so it wasn't a lot of coolant at first. I also found that a couple of the bolts that hold on that manifold had loosened over time, so I could see that leaking also.

When are these hoses blowing (miles and age)? In other words, when is the appropriate time to change them out so you aren't stranded/

Mine blew at 107K, but I wouldn't change them until they leak. It was so hard to reach, I never laid eyes on the thing until it was out. I could only see it with a mirror.

Maybe long shot but if you smell it inside the car, check your heating core in the back of center console. Did your windshield fog up easily?

2000 4.4 @ 130k

Sorry for the late response, no the windshield did not fog up. I still have the issue, didn't drive the car for a month as I was away with family. Off to indy on Monday...

The same over here. but bolts doesn't seem to be leaking, just little rust thing on it. so didn't want to touch it, It could brake. Hose changed also. But have to check under the car. could be something more.

Back from dealer, turned out to be faulty expansion tank. Removed and replaced!