Jeep Cherokee XJ Running Hot

[HoosierJeeper]

Try an OEM or Gates water pump. Same for the tstat.

My 96 runs a tick under 210 even with the AC on and sitting in traffic in 96 degree heat. So it overheats at idle and while driving, right? Could also test to see if there's exhaust gases in the coolant.

 

[Chris142]

It was 111 here today and my TJ was not happy even with a 2r all aluminum rad in it.

 

[Nick1994]

Ok. 110 degrees out and I went and drove it around with NO A/C. It never went over 210. Stopped at O'Reilly's to get some radiator flush and let it idle out there, came home and let it idle for 5 minutes, still 210. Turned on A/C for 5 minutes and idled, went to 220 and I didn't wait for it to go higher. Turned off A/C and drove around the neighborhood and it cooled to 210 and I idled in the driveway for 10 minutes, stayed at 210-212.

A/C compressor is also a little noisy, but blows ice cold air.

I called a buddy of mine who is a mechanic and he still wants me to flush out the radiator with cleaner in it for a week and do lots of drain and refills and see what that does. He thinks the coolant is real dirty from off-road driving. He'll also hook up his gauges to check A/C pressures.

 

[Syntheticuser]

Nick, just buy a better/newer jeep. Get rid of that old thing that has caused you some grief. New ones are way cooler. Man your old jeep is about to have a major mechanical breakdown. Junk it....for something newer.

 

[Nick1994]

Originally Posted By: Syntheticuser
Nick, just buy a better/newer jeep. Get rid of that old thing that has caused you some grief. New ones are way cooler. Man your old jeep is about to have a major mechanical breakdown. Junk it....for something newer.
I'll never get rid of this Jeep. My grandfather had it for 10 years before me and I'll keep it forever.

Newer Jeeps are junk, unreliable trash.

This one is very capable off-road and in good shape

 

[mk378]

By its nature, the A/C system dumps heat in front of the radiator.

Overheating with the A/C on means it is about to overheat even with the A/C off. That doesn't mean there's something wrong with the A/C. It means the cooling system is very marginal.

 

[supton]

Mechanical fan? Is the shroud in good shape? If so, I'd add another fan, maybe on top of the condensor. Only runs hot at idle, right? Sounds like airflow to me--bigger radiator might help but IMO it needs more air.

Probably can't move the condensor but if you could, I wonder if some distance from the radiator would help.

 

[jeepman3071]

Few things I would check:

1. Was the T-stat an OEM 195* or a Stant SuperStat 195*? Others can open too slow.
2. Can you verify that the temp sensor is good? (use a temp gun on the thermostat housing)
3. When the engine is hot, does the fan clutch show some resistance if you try to turn it with the engine off? (it should)
4. Since this is pre-1999, does the electric aux. fan click on when you turn on the A/C as it should?
5. When the temp hits 215-220* does that same electric fan click on?

Some things to note:

The radiator is really too small in these things. I bought a CSF 3 row radiator when mine was running warm 6 years ago, and my temp stays right at 195-200* even when towing. T-stats and fan clutches can be bad right out of the box. It might be worth replacing the cat converter also, I've seen clogged and broken ones cause the Jeep to lack power and run warmer as well.

My cooling system consists of:
-Stant 195* Superstat
-CSF 3 row radiator
-Stock replacement Napa fan clutch (not the heavy duty loud one)
-factory OEM temp sensor
-Aftermarket transmission cooler run in-line with radiator

All of the above parts have been there for 6+ years.

 

[Nick1994]

Originally Posted By: jeepman3071
Few things I would check:

1. Was the T-stat an OEM 195* or a Stant SuperStat 195*? Others can open too slow.
2. Can you verify that the temp sensor is good? (use a temp gun on the thermostat housing)
3. When the engine is hot, does the fan clutch show some resistance if you try to turn it with the engine off? (it should)
4. Since this is pre-1999, does the electric aux. fan click on when you turn on the A/C as it should?
5. When the temp hits 215-220* does that same electric fan click on?

Some things to note:

The radiator is really too small in these things. I bought a CSF 3 row radiator when mine was running warm 6 years ago, and my temp stays right at 195-200* even when towing. T-stats and fan clutches can be bad right out of the box. It might be worth replacing the cat converter also, I've seen clogged and broken ones cause the Jeep to lack power and run warmer as well.

My cooling system consists of:
-Stant 195* Superstat
-CSF 3 row radiator
-Stock replacement Napa fan clutch (not the heavy duty loud one)
-factory OEM temp sensor
-Aftermarket transmission cooler run in-line with radiator

All of the above parts have been there for 6+ years.

1. OEM from the dealership thermostat, replaced in June
2. I have not done this yet, I may just get a new sensor.
3. I'll have to try this, it spoils up nicely while driving though.
4. Yes, electric fan works perfectly
5. Yes. I also have a manual switch wired in for the electric fan and use it as needed.

 

[eljefino]

I got an XJ from my work for $150 when it blew its lower hose.

After fixing the hose, I noticed all sorts of rusty coolant. Took lots of flushing. Stupid car only had an overheat light, which never came on.

Those iron blocks shed rust, and people neglect the coolant.

Stupid rad petcock was a few inches up the side, nearly useless.

 

[Nick1994]

I pulled the lower hose today and drained out what I could. It was pretty dirty but not horrible. I used the hose and flushed out the radiator. I bought 8 gallons of distilled water and topped it off and used some Prestone radiator flush.

The inside of the overflow bottle was really bad at the bottom. It had an inch thick of MUD at the bottom! Definitely dirt and mud, many years of off-road driving in the silt has accumulated in the bottom and made it about 1 inch thick. The overflow bottle has a spout and is vented to outside. I flushed it out and topped off with distilled water. I blew through the overflow hose and it's clear now, no worries there.

Drove it 20 miles on the highway with the A/C, 220 degrees. Borrowed my grandparents Trailblazer (1/2 way to work) since from there it's all traffic. I'll pick up the Jeep tonight and get some miles on it for the flush to clean it up.

Also, when hot the clutch fan spins about 1/6 of a turn by hand, has resistance.

 

[GMBoy]

Is the radiator cap ok? The cap pressurizes the system and pressure raises the boiling points. Try a new cap if not just for being a good measure maintenance item.

Check hoses - are the collapsing and reducing flow?

The thought of the water pump vanes being corroded is a good possibility too.

 

[Nick1994]

Originally Posted By: GMBoy
Is the radiator cap ok? The cap pressurizes the system and pressure raises the boiling points. Try a new cap if not just for being a good measure maintenance item.

Check hoses - are the collapsing and reducing flow?

The thought of the water pump vanes being corroded is a good possibility too.
Everything is basically new in the cooling system. Radiator cap last week. Hoses look good.

 

[meep]

that's too much crud in the coolant - it suggests that there may be accumulated pockets of goo.

I concur that the radiator is a little undersized. That design dates back well before the 90s, from a time when manufacturers did not have as much excess capacity designed into the cooling system. Overheating, blown hoses, raised hoods were much more common back in the 80s--- and I don't recall when the cherokee was originally designed, but it was and is a classic design, one reason why it also has other good things going for it.

I liked the posts above about deeper radiators. In your heat, that may be your best play. But, it needs to get cleaned. And I think your going to need to actually flush the whole system out with water under pressure - not just a chemical flush. Pull hoses and run water in different directions through the engine, heater, hoses, radiator.

In my ZJ with a non-buffered gauge, it was normal to see engine temps change between idle and motion. The A/C didn't work in it, and I never saw it go above 220. Mechanical fan only.

-m

 

[DoubleWasp]

Looks like a good application for the citric acid flush.

 

[Rand]

Does it have a new water pump?
-Step 1
otherwise:
Seems like its operating as intended with an undersized radiator.

A/C dumps ton of heat in front of radiator raising temp.
You live in a very hot area.

if you dont want to put in a bigger radiator try upgrading the fan clutch to the stiffer model first.

 

[mightymousetech]

Originally Posted By: Nick1994






Holy [censored]! No wonder it is running hot.

 

[brave sir robin]

A couple weekends ago I flushed out the cooling system on the Electra using the method below.

1. drain coolant
2. fill with hose water
3. run engine until thermostat opens and heater is blowing very hot air
4. repeat steps 1-3

5. add two 32oz bottles of dollar store aluminum safe wheel cleaner
6. top off with hose water
7. repeat step 3
8. drive car like normal for at least two days if not longer
9. repeat steps 1-3 at least 3 times
10. fill with distilled water and coolant at a 2:1 water to coolant ratio
11. enjoy lower temps

I did this with my very well maintained system and managed to pull a surprising amount of gunk out of it.

 

[Nick1994]

Drove it with the Prestone radiator flush on Monday and Tuesday, put 210 highway miles on it. Today I drained it and got more dirty coolant out, this time I took the hoses off the heater core and clushed that too, has good flow already but I made sure it was empty. Took off other hoses and flushed through. Filled with distilled water and drove it to work today, I'll drain again tomorrow morning, it'll have at least 70 miles on it by tomorrow morning. I'll repeat a couple more times. I'm also going to figure out a filter situation for the vent on the overflow

Temps have been 210-215 max.

I have an appointment at the dealer for Monday about the catalytic converter. There was a recall for it and I'll have them check it out. If they don't want to replace it I'll order a Magnaflow cat for it.

Still looking into which radiator to replace it with.

 

[mk378]

Plain water can cause rapid corrosion. You may be doing more harm that good leaving it in there for days.