Hi from the land of OZ, i have a 96 update 4.0 cherokee auto. You've probably had this a million times, but id like a bit of info if i could please, my xj seems to run hot,ive done the viscous fan test and its o'k, radiator is a brass 3 core ive been told and the auxillary(thermo) fan works,so here go's, at 80f outside after driving for 5miles, the jeep sits on 215f to225f around mild traffic,out on the open road vabout 220f at 60mph, the aux fan comes on at 220f were the temp stays at idle aswell, ive checked gauge readings with a scangauge and its accurate. If i open the heater the temp drops by about 7f and the gauge sits almost in the middle. Ihave cut out the center of the thermostat to see what happens, the vehicle takes a lot longer to heat up,but then seems to run somewhat hotter than with it in. Im nolt used to a car running these temps as our aussie cars are normally better equiped radiator wise, are these temps a worry or about the norm , as ive done around 10.000mile country/outback driving and its never cooked and i get a quite resonable 24 us-mpg,i love this jeep and hope to do quite a few more long trips without having to many drama's, cheers.

 

How long since the system has been flushed?

 

Thanks for reply, i dont know about the flush, i just had a look at it and the a/c condensor that sits in front of the radiator has a lot of bugs/dirt in it so i might give it a clean with the pressure sprayer, hope i dont bust anything !. By the way would undoing the radiator hoses and flushing with water achieve much ?, thanks.

 

Ah, you may have found it. Blocked condenser will raise the temps. I usually use a garden hose and sprayer... I break things with pressure washers, lol. Soak the bugs/dirt so they loosen up then spray from behind to clear the radiator and condenser.

Pulling the thermostat and flushing from there back through the disconnected upper hose works fine.

 

Thanks for the tips, by the way just went for a drive 80f 10miles there ran with aircon on at 55mph, the gauge just under half all the way, on the way back 60f and ran with heater on with almost the same result, only when slowing down around the suburbs did it just go over half temp,dont know if this means anything, cheers.

 

P.S. forgot to ask ,would it be worthwhile using something like Prestone flush n fill kit to flush the motor/radiator ?, ta.

 

It's important to flush the radiator/condenser from the engine side out, otherwise you run the risk of just driving the crap in deeper. I use windshield washer liquid designed to soften dried on bugs (sold in RV stores) in a garden sprayer. To get better access with your garden hose I'd remove the fan shroud and the aux fan.

You're running a little warm for these engines but nothing a get too excited about. But a good system flushing should be done a regular maintenance anyway. I've used Prestone for years and it works. I flush the system until the water runs very clear. I hold a glass full up to the sun and see how clear it is. Then I used distilled water and the usual 50/50 mix. Some people in our southwest run 60/40 water/coolant to keep their engine temps down a few degrees.

 

Thanks heaps for your assistance , this jeeps done 120k miles now and everything still works as it should , so hopefully i can get a bit more trouble free motoring out of her yet !,cheers.

 

Well gave it a big flush, tried the fan test(viscous) and it works,can see water churning in top of radiator and one hose is cooler ,so i reckon the pump works,thermo fan works aswell,even cut the center out of the thermostat , all to no avai !, sits on about 215-220 on the open road and around 225 in traffic. Put scangauge on car and reading is same as on dial, one more thing left, im gonna put a temp sensor on the thermostat housing to see if its o'k' and matches temp gauge, if that turns out o'k' i'll give up and try not to worry about it !,cheers.

 

Forgot to add, running the heater drops temp by about 10f degrees, about where id want it.

 

Did you notice any crud when you did the flush? What did the inside of the radiator look like? (as best as you can see in there, lol)

 

No crud,from what i can see the radiator is ok, if i could get it to run 5-10f cooler like when i put the heater on id be happy !,cheers.

 

any idea of the age of the water pump there not all that expensive might want to consider that if the rest of the system seems clean. the impeller fins do rot away after some time perhaps just pull it and inspect it

 

Looks like my next step,thanks.

 

Hi everybody again, just a follow up, tested with a digital temp sensor, gauge on dash seems to be running about 6f degrees hotter than it actually is, (tested the tester on another car and ok) and temp diff between up and lower hoses is about 40f degrees so i think its all roughly within specs after all, cheers.