I have a 91 XJ whose temperature consistently climbs while driving. It will climb almost to the red at the end of the thermostat. I have auxillary fans that I run constantly while driving. I am contemplating upgrading to a flowkooler waterpump. My questions are:
Which water pump will best suit my needs?
How hard is a water pump installation?
Should this fix my problem? If not, then what else?

 

I'm going to assume that you've checked your coolant and you have a sufficient amount. If not, check it. If the coolant is brown and dirty, you might need a radiator flush.

After that, I would take a good look at your thermostat. This could very well be your problem and is much easier and cheaper to replace than a water pump. Once you get it out, you can boil it on the stove (with a thermometer) to see if it is opening and closing at the correct temperatures.

When a water pump goes bad, it typically makes a chattering noise around the shaft. That is the bearings falling apart. It will also begin to leak from the weep hole. (small hole on bottom side of water pump) Water pumps are not fun to replace, but not impossible for the weekend mechanic with some tools and patience. If you decide to replace the water pump, I would strongly suggest buying a service manual for you Jeep.

Good Luck. Let us know what you find.