Proper belt tension doesn't hurt either. Ditto on the aftermarket thermostats, I had a Stant bad out of the box.

 

I had 4 of them bad outta da box.

 

The Motorad cap I put on my 94' 5.2L Dodge leaked right out of the box last month and new waterpump leaked out of the weap hole after a week. Getting good parts these days is a crap shoot. What's a good brand fan clutch for 98' 4.0L, Hayden?

 

A lot of the problems with parts is that they're made by WunHungLo and his buddies in china.

 

Or parts from TangWang..
Last water pump I put on my 4.0 was from Jeep. Was expensive but I did not care. I want it to last.
I get very picky on what I buy for reliability..

 

I have a 89 Renix, converted to open system with an inline neck, I live in Costa Rica so no need for a thermostat or anything like that, it is always warm, even in winter.

Changed the mechanical fan for an electric, just because I don't like mechanicals.

Temperature on my jeep comes up right to the middle in about ten minutes, and then the two e-fans turn on and keep the cycle on and off while being parked, if I'm moving from 0 to about 20, the fans keep cycling on and off, but if I'm doing more than 20 they are off all the time.

Have not seen more than 230 in a really hot day and with heavy traffic.

Before I got it, the previous owner said it overheated really easy, I only fixed a really small radiator crack, converted to open system and added a regular overfill bottle in place of the plastic bottle, have not seen any overheating signs ever again!

 

130,000+ on the '99. 425,000+ on the'96. 250,000+ on the 96 and every (three times) time I've had cooling issues has been a direct component failure and replacement.

Auxiliary fan
Water pump
Radiator (today, go figure)

Up and down mountains, pulling stupid weights and sizes of trailer, California and Arizona deserts and no cooling mysteries. Well, except this one. Each time there has been a failure, it only fully exhibited itself at or within minutes of reaching a destination.

Now that I think of it, in the multitude of dubiously maintained cherokees and comanches I've used overseas in the Army, not a single failure that I can recall.

 

What you need is an auxiliary vent.