Hot running XJ

I know this has been asked before, but I have searched and not found anything I haven’t tried. First the details, 88 XJ, 4.0l, auto, 231/300 doubler, 30/44 w/ 4.10 gears and lockers, 33” Truxus. I swapped to a 2-core GDI open rad. about 3 years ago. 195* T-stat works. Hoses are good, no spring in the lower hose. New water pump. I have hood vents and the back of the hood propped up ¾”. I have the tranny going through the rad. and a cooler. The clutch fan is bad and will be replaced this weekend. Now the problem, when I drive on the highway the temp climbs to 220 plus. I have to turn on the heater to bring the temp down. Driving around town w/ the temp at 90* plus. I have to have the A/C or elec. fan on to stay at 210*. I have not actually over heated where water spits out or gone to the red on temp gauges. (I’m running two temp. gauges. The stock one at the back of the block and an after market one at the t-stat housing.) Is there any thing else I could try? The next thing I might try is a single core alum. rad. And maybe remove the two lights in front of the grill.

wait till you change your clutch fan, then see... that sounds like it will fix it

Definitely change your fan clutch, but I doubt that's your highway problem. If the heat brings your temp down, sounds like you have a capacity problem, which most likely is manifesting itself the radiator; the heater acts like another radiator. RichP always offers the same general guidelines around here; overheat idling/traffic bad fan clutch and/or electric fan not working, overheat on highway radiator is shot.

I agree with the others, do your fan clutch first, I doubt that will help on the hwy. If you decide to go with a new radiator, there really is no reason to go with a way overpriced premium aluminum radiator (and the "premium" cooling performance is definitely debatable). I use a $170 3 row csf radiator that fit great and works great.

Ok I have changed the fan clutch twice. Maybe I don't understand how the clutch works. While cool it should have little resistance, while hot should have alot of resistance if not completely locked. The first was a used one from a wrecking yard. Put 10 miles of in town driving never engaged. Checked clutch fan when the elec. fan came on at 220*. If any thing it spun easier when hot. Second clutch was a new one from Napa. Went for a trail run on Sunday, Jeep never got that hot before. Stopped when temp passed the line right before the red on stock temp gauge. Fan spun same as cold engine before trip. Called the dealer, they want $171.50 for a factory clutch. I do have a good fan shroud. What about a flex fan? Or an electric replacement?

opracer315 said:

Ok I have changed the fan clutch twice. Maybe I don't understand how the clutch works. While cool it should have little resistance, while hot should have alot of resistance if not completely locked. The first was a used one from a wrecking yard. Put 10 miles of in town driving never engaged. Checked clutch fan when the elec. fan came on at 220*. If any thing it spun easier when hot. Second clutch was a new one from Napa. Went for a trail run on Sunday, Jeep never got that hot before. Stopped when temp passed the line right before the red on stock temp gauge. Fan spun same as cold engine before trip. Called the dealer, they want $171.50 for a factory clutch. I do have a good fan shroud. What about a flex fan? Or an electric replacement?

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Get the 4 Seasons XHD fan clutch. PN 36942. It should solve your overheating/bad fan clutch problems.

-RR

went through the same thing i wired a switch to my AUX fan. when wheeling i ran it as soon as i got to the place and was running like new, and on hot days in stop and go traffic i run it and it works wonders. no more :flame:

Why did you take out the wire in the lower hose????? That is there to keep the hose from calapsing at higway speeds from the pump pressure. If the hose calapses then you lose flow to the block which will cause it to heat up and act like a blocked radiator. Put the wire back in. I ve had real good luck with using a robert shaw thermostat, little better flow rate. Also replace your radiator cap if you havent all ready.

RichieRich said:

Get the 4 Seasons XHD fan clutch. PN 36942. It should solve your overheating/bad fan clutch problems.

-RR

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Got a link to this part??

llibobill said:

went through the same thing i wired a switch to my AUX fan. when wheeling i ran it as soon as i got to the place and was running like new, and on hot days in stop and go traffic i run it and it works wonders. no more :flame:

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Aux fan already wired done. I had the aux. fan and the heater on full still running way to hot.

jeepme said:

Why did you take out the wire in the lower hose????? That is there to keep the hose from calapsing at higway speeds from the pump pressure. If the hose calapses then you lose flow to the block which will cause it to heat up and act like a blocked radiator. Put the wire back in. I ve had real good luck with using a robert shaw thermostat, little better flow rate. Also replace your radiator cap if you havent all ready.

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The spring was gone when I bought it. Can't find a replacement, the wrecking yards cut the hoses to drain them.

Dealership is where I got my hoses, the lower one with the spring. To me it sounds like your radiator is the culprit... I know it's only 3 years old but just ask Blaine B how long a new radiator can last before causing serious cooling problems:smsoap: