Okay, It will cool properly at road speed but not at idle would indicate fan
failure to move enough air as a primary concern. If you can send me an
e-mail address I'll forward you some Jeep Cooling System info.

Overheating In Traffic (Stop and Go, Low Speed Driving)
Overheating in traffic and low speed driving has one common cause: the fan.
During stop and go, low speed "creeping" and low speed driving, there is not
sufficient flow of air through the radiator. Therefore, the engine has a fan
to draw air through the front of the car. This fan operates off of a viscous
fan clutch. Basically, the fan clutch is mounted between the fan and the
engine. As cold air flows over it, the clutch loosens up, allowing the fan
to freewheel on the shaft of the engine. The fan then hardly turns. As the
air flowing over the clutch heats up (as the engine transfers more heat to
the radiator) the clutch tightens up, spinning the fan faster and drawing
more air through the radiator. The cycle continues as long as the car is
running. Over time, this fan clutch can wear out, causing the fan to
freewheel whether it is hot or cold. This causes reduced airflow through the
radiator, and therefore high operating temperatures during low speed
driving. This theory is easy to test, because once you get on the highway
the car will cool right down.
Testing the fan clutch is pretty easy. Simply start the car and allow it to
warm up to normal operating temperature. Shut it off, then give the fan a
good flick with your hand. If it rotates more than about 1.5 turns, then
odds are the fan clutch is worn. However, I have found this test to be a
very bad indicator of the true condition of the clutch. A much better test
is to simply pick another one up and swap it on. If this solves your
problem, then the fan clutch was obviously the culprit.


"YouGoFirst" > wrote in message
...
>> The chances of everything failing at the same time is pretty small. That
>> being said it is possible that multiple components were in the process of
>> failing and it only took one additional event to provide the strain to
>> throw the rest over the edge (so to speak)
>>
>> PS
>> Do we know why the original cooling system failed a year and a half ago?
>
> Yes, it had developed some leaks and was leaking antifreeze.
>