Hello I'm working on a 1990 xj and covered to a open system. I replaced the radiator with csf 2 core I also replaced the thermostat and the fan clutch. The problem that I'm having is when driving the temp stays right at 210 but at idle it creeps up slowly. I have the aux fan on a switch and will bring down the temp but my question is should the mechanical fan be enough to cool the system down at idle? Did I get a bad fan clutch (cheap one from autozone)? Could it be my water pump? Any help would be great. Thanks

 

I'd say to go ahead and throw in a new water pump. I'm sure you'll see a nice improvement. The most stress is put on the cooling system at idle since there is not much airflow other than what the fans bring in. This is why you need coolant flow to be at its best, which is the job of the water pump. So if it were me, that would be my next step

 

The electric fan kicks on in both my Jeeps at about 212* and cools it right down. Normal. and no, the vehicle was not designed to run on the engine driven fan alone.
Knowing you've got a new water pump on there would be good also. When you replace the thermostat, use the one from the dealer. Way more stable temps in both summer and winter. 83501426.

 

I thought I read that factory non-a/c XJs (though rare) with standard cooling, did not have a factory installed efan, no?

 

A couple of questions for you. What temp is on your new t-stat? How high does the temp go up?

 

And they didn't have an AC condensor in front of the radiatorif that's the case.
Not sure. Here in Arizona I don't think we ever delivered a 4.0 XJ or MJ without AC. .

 

I replaced thermostat with a 195 when it 1st warms up to around 200 I can see when it opens cause I see the gauge drop to about 195 then warms up again it does this a few times then I don't see the drop anymore it just climbs slowly

 

In what kind of driving conditions do you observe this?

 

Normal driving

 

Worse at highway speeds? Better at highway speeds?

 

Still waiting to find out how high your temp climbs up to???
I can drive my 98 XJ all day in south Texas in 110deg weather and I did this yesterday. My temp will stay between 210 and 212 all day long.

 

Help, I have a 87 Cherokee that once a year overheats, and blows out the coolant tank. Is there a way that the pressure can release without expanding the plastic tank? And what causes this?

I may have entered this into the wrong area, sorry for that if I did.

 

When driving temp is fine stays at 210 but when stopped and idle it climbs. It will get up to about 230 and keep climbing i never let it get past that

 

I'll bet there's never been ANY car delivered to AZ without a/c. Anyhow.....it's my understanding that standard cooling (no factory a/c) consisted of the clutch fan only and if that's the case, I presume it kept the motor cool enough.

 

Fan shroud in place/intact?