The first day over 90 degrees we looked down to find the engine temp at 240 degrees and creeping towards the red. While we sat on the side of the road waiting for the truck to cool, we had time to ruminate. The radiator was only a year old and a good three-core unit, so we doubted that was the problem. The water pump and thermostat were also good. The electric fan was working and since it does such a small portion of the actual cooling, we turned our sights on the factory fan clutch. It didn’t feel particularly loose, but this unit from our local Napa Auto Parts (PN 272310) intended for a ’97-’98 Grand Cherokee will out-pull the factory Comanche clutch any day. There is less slip inherent in the clutch, meaning that it pulls harder and puts more air through the radiator.