"Capacity Problem Relating to the Cooling System"

I did a search and found this. What exactly is a "Capacity problem? What repairs need to be done? When driving during the day with temps 90* and above temp gets up to 240*. I turn on the heat on high and the temp drops to 210*. In the evening with a/c on temp stays at 210* to 220* which has been pretty normal since I have owned the jeep. It is a '96 Classic, AW4, 4.0 HO.

Thanks in Advance.

XJ's normally need a new radiator around 100,000 miles. Our systems don't have much reserve cooling capacity so they don't tolerate much of a decrease in cooling system performance.

If the cap is holding pressure, and if the aux fan is coming on, and if the clutch fan is in good condition, then a cooling proplem is just about always a partially plugged up radiator. Take it to a radiator shop to have it rodded out, or if it's the original radiator replace it with a good aftermarket one. Be sure to back flush the motor before you install a new radiator or you can eventually plug up the new radiator.

Most XJ's have a single core radiator that's marginal at best even when new. If you live in a hot country as I do, you may be lucky enough to have the factory heavy duty cooling system which includes a two row radiator. Do yourself a favour; swap in a 2-row Modine and follow Goatman's advice about flushing the cooling system (that includes the engine's cooling core) first.

Ditto what Goatman and Dr Dyno said. The XJ cooling system needs to be in tip top shape in order for it to do its job. I would call the cooling capacity "adequate" when every piece in it is working properly. When there is problem with any of its compenents then the cooling ability of the system goes south rather quickly.

_Maz