My 1996 won't stop running HOT!!!

Just like the title says, but I don't know what else to do. It has a brand new radiator,new water pump, new heavy duty clutch fan, recently flushed cooling system with a new thermostat, new upper radiator hose, and recently added a tranny cooler too, but it still runs hot. It only really gets hot when I am running the A/C though. I have tried everything I can think of, and it is really starting to get to me. Do the post 92 Cooling systems need to be burped?? Also my A/C compressor never cycles off when the A/C is running is that normal?? Please if you have anything you think might help let me know. I am almost to my wits end. I love my XJ, but I am to the point where I am thinking about just selling it.

I'll be Captain Obvious for a minute and ask if you've checked the accuracy of the gauge.
Have you checked the accuracy of the gauge?

Well I haven't checked the accuracy of the guage, but I know its running hot because its boiling over into the overflow container. I also put on a brand new 16 psi thermostat when I did all of the other work.

Is your electric fan working? It should come on anytime the AC is on. While checking its function, make sure it has all its blades and the shroud around it!!

By the way you describe your A/C functioning, it is possible it might be a tad low on refrigerant. If it blows cool, I would not worry too much if the compressor stays on.

I try to get all the air out of my 96, by making sure the reservoir if up to the full mark, then running the Jeep up to operating temperature then letting it cool down then check the reservoir and add more coolent as needed. I usually do that 2 or 3 times before I am satisfied it is full.

is t-stat from the dealer? thats only place to get them from..

Why is the dealer the only place to get a t-stat from? i run a 180 hypertech t-stat and its fantastic....

The electric fan is operating just fine..... clicks on anytime the A/C is on, and also clicks on and off like it is supposed to when the A/C isn't on. I did just use an Auto Zone thermostat. I am going to get one from the dealer tomorrow, and replace it. We'll see if that makes a difference. I have a question..... on a 96 is there any way to hook up an aftermarket mechanical temp guage?

Sure there is. You will need to adapt the t-stat housing where the sensor is. Some pipe and a t fitting should work OK. Looks funny though.

To burp my 96, I park on a slight incline(or jack the rear up), nose down and remove the coolant sensor at rear drivers side of head. Fill it until coolant comes out there and then put the sensor back in, pull it on level ground and top it off.

JNickel101 said:

Why is the dealer the only place to get a t-stat from? i run a 180 hypertech t-stat and its fantastic....

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I used to run lower temp tstats and now I have absolutely no idea why. The engine is not designed to run at 180 degrees. I used to think it would help an overheating problem, but I should have just listened to all the guys on this forum who really, and I mean REALLY know their XJs. I went through a Mr. Gasket and 3 different stant tstats before switching to a dealership 195, and now everything is perfect.

Regarding the cooling problem; does your jeep overheat on the highway with the a/c on? Also what about the lower rad hose?

from what i hear everybody say go to dealer, then they say holy crap it works

Well, if he is boiling over, it is running hot.

I've had bad experience with AutoZone thermostats keeping the Jeep too cold in the winter (not allowing my heat to be warm)

Stant Superstats or OEM Dealership thermostats were good though.

If you replace the gauge sender at the back of the head, only buy that part from the dealership. If you want to replace the coolant temp sensor at the thermostat housing, you can buy that anywhere.

Make sure you bought a reverse rotation fan clutch, and installed the blade on it in the correct direction. Also is the water pump a correct flowing pump?

xjtrailrider said:

To burp my 96, I park on a slight incline(or jack the rear up), nose down and remove the coolant sensor at rear drivers side of head. Fill it until coolant comes out there and then put the sensor back in, pull it on level ground and top it off.

Click to expand...

With the open system you really don't need to do that... especially with the dealership tstat with the bleed hole (or other well-designed tstats). I just leave the cap off the very first time I fill up the rad and keep adding it after the tstat opens, heat on; after the level quits going down, any remaining air is minimal and will work its way the overflow

The lower radiator hose is good, and still has the spring in it. It will overheat on the highway, freeway, or city driving, but only if the A/C is on. It still runs a little on the warm side without the A/C on, but I am guessing the A/C being on is just the tiny extra it needs to run really HOT. I am going to go ahead and swap to a dealer thermostat tomorrow, and while I have it apart I might as well flush it (AGAIN). Then I guess I will see how it goes from there.

Before I replaced my radiator, my jeep would overheat on the highway slowly with the a/c on, run fine without it, and go down a bit when i would turn the heat on. Does your temp go down if you blast the heat? How long ago did you replace the rad, and what kind is it? There is a possibility that there was a bunch of junk still in your block when you changed rads, along with possible shipping/packaging crap still in your new rad that has restricted flow (a flush will do very little to unblock a restriction, unless you get lucky) because it sounds like you have a capacity problem. Did you fill it with tap water or distilled water (or 50/50 premix)? Tap water can gunk up a rad fast.

There are other possibilities unrelated to your cooling system itself (i.e. plugged cat, lean timing) but I really don't think these things are too common, especially if the rest of the cooling system is in good working order. Not saying it isn't possible, but unlikely.

It is just a two core radiator that was put in there about 2 months ago. It was filled with distilled water, and about 35% Prestone Coolant. The cat isn't clogged because it hasn't lost any power, and how do you adjust the timing on a 96? Also the temp doesn't really go down with blasting the heat.

ive ran my xj with a 180 tstat for over a year now ... and i love it... it stays there even( only at stop an go traffic does it go to 210) in the 100 degree weather were having , i know there not designed for it, but having the jeep run cooler than hotter to me it nicer to me....srry to steal this thread back on topic...

With a plugged cat he'd have a decrease in power. With a timing issue it wouldn't run quite right and would backfire and such. Would have difficulty starting it too.

Also the thermostat's temperature only specifies when it opens. If you are running that cool in 100 degree weather, you have the rest of your cooling system to thank - not the thermostat. Once it is fully opened and such, it cannot regulate keep the system cooler. That is the job of the radiator, coolant mix, and fans. The thermostat only helps the vehicle warm up faster and keeps it from getting TOO cool. It can't keep it cooler than a higher temp thermostat though.

Well, a lower temperature tstat will keep the temperature lower; IF you have a powerful cooling system. Think about it; if your cooling system is marginal and can only keep an engine running at 215 during normal operation, a 180 tstat will open completely earlier and circulate all the coolant 15 degrees earlier than a 195... hence, the temp will warm up 35 degrees, albeit with all the coolant circulating. A 195 will open 15 degrees later (duh) and will have to move up 20 degrees fully circulating. So if you're only going on short trips or low stress situations, a 180 will keep your cooling system running at a lower temperature.

Now, if you have an upgraded, powerful cooling system that is actually capable of keeping the jeep at 180 even in tough operating conditions, then yes, a lower temp tstat will keep your jeep running cooler. Here's the thing you need to ask yourself though. If your cooling system is that good and can keep the jeep at 180, then obviously it can keep it at 195. And your engine management strongly prefers 195-205 (tstats tend to open about 5-10 degrees later than rated due to pressure, unless you have a balanced design). I realize it seems easy to think that you have more breathing room if you start at 180 versus 195 if you start to heat up, but the end result will be the same and it's better to run at the OEM recommended temperature.

Blackdoutxj, your post backs up exactly what Blaine said; when you're not in strenuous conditions, your jeep runs at 180... when you're in tough stop and go idling conditions, you reach 210... just like you would with a 195. Except with a 195 your engine operating range is 15 degrees, instead of 30 degrees.

I ran a 180 for awhile too and got used to how my jeep ran. But when I switched to a 195 my jeep idled smoother when fully warmed up and I got about 1 to 1.5 more mpg.

x2 on the auxiliary fan. Change out the sensor on the TSTAT housing for fun. It's cheap and you probably need one.