1990 XJ overheating problem

[fdsa487]

So... my uncle bought an XJ. It’s a 1990 4.0 with the older closed style cooling system. He had it converted to on open style cooling system and a 3-core radiator installed.

It drives fine and does not have any overheating problems on the road. As soon as he takes it off road and starts wheeling it the Jeep beings to overheat.

What would he need to do to solve this overheating problem? The fan in the Jeep is really far away from the radiator compared to newer XJ's. What is the deal with that?

We thought that what we have already done (the open style conversion and the 3 core radiator would have solved it) but it did not help the problem.

He wants to know if an electric fan would solve the problem and what one you guys would recommend. Maybe dual electric fans would solve the problem? :twak:

[POSXJGuy]

make sure the fan you are using is pushing enough cfm for that xj. if the fan clutch is bad its not gonna work right. better yet, do the taurus fan switch with the 2 speed taurus fan and you'll have control over it. sounds like the problem is the fan. is there a fan shroud on ther as well?

should be a relatively easy fix. go through all hoses, t-stat and make sure coolant / water ratio is right. should be fine. stay with the oem temp tstat as well.

if everything is in place it shoud be fine.

[90red]

It might be that your fan is too far away from your fan shroud and it isnt pulling enough air through the radiator. When you are on the highway, there is plenty of air moving past the radiator. It could also be your fan clutch isnt working properly. An electric fan would probably work, but you should make sure that you get one that moves plenty of air. Something around 2000 cfm should be plenty. Somehow getting the fan closer to the radiator and into the shroud might be a much cheaper and easier fix.

90red
Alex

[87manche]

is this an auto or manual?
THe 5 spds didn't come with an aux fan, when I wheeled this summer I pegged the temp gauge, it just got heat soked, and at 3-4 MPH in 4-lo there just wasn't enough airflow.
A hayden 10" fan solved that problem nicely, now wheeling temps on my closed system MJ are about 220. This was in 100* ambient temps.

[fdsa487]

is this an auto or manual?
THe 5 spds didn't come with an aux fan, when I wheeled this summer I pegged the temp gauge, it just got heat soked, and at 3-4 MPH in 4-lo there just wasn't enough airflow.
A hayden 10" fan solved that problem nicely, now wheeling temps on my closed system MJ are about 220. This was in 100* ambient temps.


Its an automatic

[87manche]

well if it's an auto it should have an aux fan, is it working properly?
Have you checked the water pump and what kind of flow you're getting out of it?

[fdsa487]

well if it's an auto it should have an aux fan, is it working properly?
Have you checked the water pump and what kind of flow you're getting out of it?

Im pretty sure that his aux fan is working property. I dont that that he has checked the flow of the h20 pump yet, but we'll get on it!

[90red]

I have a 5 speed and it came with an auxillary fan from the factory.

90red

[nickangus]

my 91 5sp came w/ aux fan too

check the fan clutch for the motor driven fan
also check the temp that the aux is turning on mine wanted to turn on at 225ish way too late
i wired in an override so now i have full control

[87manche]

my MJ didn't have AC, no AC+5spd means no aux fan, not even the wiring harness for it.
I should have clarified that.