My 1989 XJ was starting to overheat at idle which I wasn't going to tolerate it for one second.Ê The cooling system is an often overlooked area of Cherokee's and I'd be willing to bet quite a few premature engine failures were due to overheating.Ê Quite often during the summer months Cherokee's are seen stranded on the side of the road with the hood up, suffering from lack of cooling.

A well maintained 4.0 should easily reach 200,000 miles, but if somewhere during it's life the motor overheats into the 240 degree range and beyond, the life of the motor can be severely shortened.Ê Piston rings and bearings don't like excessive heat and when they do metal changes occur which change the strength and life of internal engine parts.Ê

Part one will describes the install of a Flex-A-Lite #110 Cooling Fan, and A/C Cooling fan upgrade.

My fan clutch was not working properly at idle and therefore not pulling enough air through the radiator.Ê At idle speed the fan needs to keep a high volume of air moving through the radiator.Ê Any fan is effective up to about 35 mph and then the air flow running through the radiator takes over.Ê

One way you can tell if your clutch fan is working properly is to drive the vehicle until operating temperature is reached.Ê After you turn the engine off, immediately lift the hood and try rotating the clutch fan by hand.Ê There should be some noticeable resistance due to the fact the viscous fluid inside the clutch fan is temperature sensitive and will lock-up the fan at a set temperature.Ê As the motor cools the fan reduces engagement so drag is not constantly put on the motor.Ê When clutch fans wear out they do not fully engage and therefore do not pull the correct amount of air.

The benefits of an electric fan are that you get increased power and mileage, the fan moves 100 percent air capacity whenever it is on, and you can control whether it is on or off-useful during river crossings. I have noticed increased mpg in town and more power due to the fact that the motor is not having to spin a five pound weight all the time.

The Flex-a-lite model 110 is the lowest profile fan Flex-a-lite makes and a good thing since it is just the right size to fit a 4.0 equipped Cherokee, although it is a universal fan not Cherokee specific.Ê The 110 comes as a kit with everything you see here and is thermostatically controlled.Ê An optional electric dash switch can be installed to allow manual operation.

The first installation step is to remove the clutch fan and shroud by simply unbolting it from the pulley hub. After you pull the fan out make sure to re-install the fan-retaining nuts and washers onto the hub and tighten them securely.Ê The clearance is very tight between the radiator and the engine pulley but the Flex-a-lite is exactly the correct size-almost like it was designed for an XJ.

The mounting studs for the clutch fan are just long enough that they interfere with the new electric fan.Ê The studs need to be cut off flush with the top of the four bolts on the pulley.Ê A hacksaw will work, but an air-powered saw worked much better.

With the pulley studs trimmed and the clutch fan removed it is now necessary to trim the lower fan shroud tabs on the radiator to allow room to mount the electric fan.Ê These can be bent down or ground off to provide clearance.

Now slip the 110 fan into the housing and make sure there is clearance between the pulley and the electric fan.Ê A high quality rubber gasket is built into the Flex-a-lite which cushions firmly against the radiator to provide its own shroud effect.Ê The fan is not perfectly square so make sure you mount it with the widest side horizontal to the radiator.Ê The fan will overhang below the radiator if it is in the wrong position.

The best way to mount the Flex-a-lite was with the included plastic brackets. The top two brackets were longer than needed so they were ground down to clear the hood. Ê You can see in the photo how the brackets attach to the top of the radiator support.

The lower brackets required two pieces of metal "L" brackets be mounted to the frame to allow a spot to bolt the plastic Flex-a-lite brackets.Ê With the upper brackets attached it is apparent how the lower brackets will need to be attached.

With the fan mounted securely, the hard part is over.Ê Now you can mount the control box right below the hood support clip on the passenger fender well.Ê I used double-sided 3M tape and found this to work out easier than trying to bolt it to the fender.Ê Make sure the the coolant sensor bulb can reach inside the upper radiator hose before you mount the control box.

The bulb-type temperature sensor slides into the upper radiator housing and then the upper-radiator hose is mounted over it.Ê Full fitting instructions for the sensor as well as wiring the control box are included with the Flex-a-lite fan.Ê As mentioned earlier, an optional switch can be installed to have manual control of the fan or the adjustable control box can automatically handle cooling duties.

A final upgrade at this point, for pre-1993 Cherokee's is to replace the A/C electric cooling fan with a 1993 Cherokee or newer A/C fan due to a design change which pulls more air than the older style fan. Since the two fans are the same dimensions, installation is as easy as removing two bolts on the old one and installing the newer style in its place.Ê Make sure to also re-connect the power plug.Ê The photo clearly shows the superior design of the new fan on the right compared with the pre-93 fan on the left.

If you order a new A/C fan from Mopar it supersedes the old style. I purchased my 1994 A/C fan at a wrecking yard for $40, a new Mopar fan will cost $90.

I bought the Flex-a-lite fan for $89.99 from Jeg's High Performance at 800-345-4545 or you can call Flex-a-lite Consolidated at 800-851-1510 for literature and the dealer nearest you.Ê Ordering by mail from Jegs of Summit is the least expensive method, and it comes right to your door.

Plan on taking two hours to complete the install if you do it yourself or have a shop perform the work.Ê It cost around $80 when I enlisted the expert Jeep services of Jeff's Welding and Automotive Repair in Albion, WA at 509-332-3629.

The next few parts of "Cooling System Upgrades" will include: The install of a high-performance water pump from Flow Kooler; Radiator and transmission cooling fluids from Pro-Blend; Radiator replacement options; Mopar oil cooler; Thermostat suggestions and wiring the two electric fans together to provide manual control of cooling.Ê

Stay tuned as Cherokee America teaches you how to defeat your cooling system problems forever!

By - Randy Harris