matholland

Ok guys so I have a 96 Cherokee Ive had for a while now thats my trail rig. This started sometime this past winter and I thought I had it all taken care of. I havent been using it much for a trail rig so it has been sitting in the barn most of the summer. At the last part of winter I did the following
Pulled the head off and had it redone with new valve seals
New lifters
New water pump
New radiator
New 180* thermostat
New upper radiator hose
New radiator cap
Grand Cherokee fan clutch
97+ electric fan
I put hydro assist on the Jeep over the winter. I put a transmission cooler up front on the passenger side of the radiator so that the electric fan pulls through. Electric fan wired up to a toggle

Im getting ready to change that to a heatsync style cooler just to see. I dont think thats the issue though. I am wondering if maybe my condenser is blocking some flow. Idk I feel like thats the only thing left to change that I havent changed out.

95 degree day ac running going down the highway and Im getting up to like 232 running down the highway. Im out of ideas.

OutbackOz

I had the same issues with my 96 I did everything to it head rad water pump zj fan and still ran hot? its because you get scale in the water galleys and don't transfer the heat to the coolant efficiently

I found this stuff called Liquid Intelligence 239 ......... Google it youtube it Aussie made its a part A and part B flush look it up it works I did my 96 and are doing my 99 you get enough for 2 cars take your thermostat out to flush cut some stockings and catch the rubbish from your top hose going into the rad and you will be amazed .... and cool again

GzrGldr

Had similar issues. ZJ fan clutch helped a lot. Also, check your lower radiator hose. Mine was getting pinched on the power steering lines, so had very little flow. I had also replaced the original lower hose and the new one did not have the spring in it. Make sure there is a spring in it so it doesn't collapse. Then burp the crap out of the system. I went from overheating on any incline and having to pull over and cool down to being able to climb any mountain pass without the e-fan ever having to come on. Also, my thermostat had an air hole with a small detent in it. MAKE SURE THAT DETENT IS ON THE TOP when it is installed. If yours doesn't have that, then some people make a 1/8" hold in it to help burp air out of the system.

Those 3 things took mine from overheating on a regular basis to being able to pull miles of long mountain passes with no problems. I just did mine and tested it yesterday and climbed a pass with an elevation increase of 4000 feet, as well as several other passes that I couldn't make it up before without stopping several times. I even used the AC on some of them with no problems.

Believe it when people tell you that the stock cooling system is sufficient if it is installed properly. I threw several aftermarket parts after my cooling system trying to resolve issues and all I really had to do was use the right parts in the first place.

matholland

The lower radiator hose is something I have not looked at yet. I will take a look at that and see if it is collapsing on my lunch hour.

I'm confident all of the air is out of the cooling system, I as well drilled an 1/8 hole in the thermostat, that's a trick I learned a long time ago, and have done it ever since when I put a new one in. Old one actually had a hole in it as well.

I believe it, I have had 6 or 7 cherokees/grand cherokee's, and I have never had an issue with them getting hot unless I was on the trail sometimes, they also like to vapor lock. All of the parts I have replaced have been stock replacement parts, except for the grand cherokee fan clutch. When I was driving it towards the end of winter after I did this stuff, I thought it was fixed as it was staying under 210, but now that it's hot outside, that isn't the case.

One mod I am planning on doing, is getting a ford taurus efan, and making it fit in place of the fan clutch. I know that isn't going to help my heat issue, I don't want to do this until after I have this jeep running under normal temp, but since this spends 90% of it's life on the trail, i'm wanting to do it for cooler temps at low speed trail runs.

matholland

Lower radiator hose is not collapsing...doesn't have a spring in it, but it doesn't seem to be collapsing when I rev up motor or anything. With my cheapy ir gun, radiator is getting around 150...top hose is pretty tight @ 225....If I spray water onto radiator it starts dropping down and AC cools off.....when temp gets up to 215-220, ac might as well not work at all as it's just warm air.

matholland

It's been a while and I figured I would do an update....

I bought a new AC condenser and drier because my old condenser was looking pretty bad and I thought it could be limiting some airflow. I charged up the AC, and I also converted the jeep to a single ford taurus fan. No I didn't do this to try and fix my heating problem. I did this because the jeep rarely gets driven other than on the trail, and I figured a good efan would keep things cooler at low speeds on the trail. When it is warm outside 90+ and I run the AC, then the jeep will start to get hot. I am really at a loss here....my plans was to turbo this XJ, and I can't do it with this thing getting hot. Once the weather cools off, I don't have this issue, so I don't know what else to do.

Here is a recap...I had an issue with it creeping up and getting warm along with smoking when it was at a steep incline.
Head was pulled off, took to a machine shop and redone with new valve seals. New head gasket, new lifters. I put in a new water pump, thermostat, radiator, upper radiator hose, radiator cap, grand cherokee fan clutch with the 97+ efan....still got warm....ended up putting a new condensor in, changing to electric ford taurus fan, moved the transmission cooler I had in front of the radiator for my hydro assist out of the way and switched to one of those tube heatsync style's, flushed heater core and radiator just because it was free, went ahead and put a new temp sensor at the thermostat, just to make sure it was reading correctly with my scanner....still no change....still wants to get warm....I'm at a complete and total loss, and I don't know what to do in order to stop this from getting hot.

Griffyorcono

If you have not pressure tested your cooling system you need to and that is what I would do if you brought your XJ to me. The first thing I started with was replacing both hoses and making sure the lower hose has a spring in it so it doesn't collapse. I've been told this 10000 times and so I'll be the old grumpy guy that says it too. BLAH BLAH BLAH THE JEEP XJ SYSTEM SHOULD NEVER RUN HOT IF ALL THE COOLING SYSTEM IS REPLACED AND TESTED PROPERLY XD. They're not completely wrong though sadly... So based on that the ZJ clutch is not needed and just a crutch for an underlying problem so is removing the ac condenser unless it is really completely blocking flow, same with the Ford Taurus fan . Also I don't want to always scream headgasket problem but did they machine the block aswell or just the head? Because block flatness is just as important as head flatness so that would be where a head problem would be coming from even after the gasket is replaced.

Goodluck and keep us updated. Photos would be helpful just cause someone might be able to say that something is clearly leaking that you may not realize with your own eyes.

Thank you and good luck,

matholland

I have done both a pressure test and used a head gasket tester and both passed. While I have not replaced the lower hose, I have revved the **** out of it while holding the mower radiator hose and it does not collapse. Apparantly you cannot buy one with a spring in it at a parts store so you would have to get one from a junk yard and I haven’t had a chance to go to the pull a part an hour away on a sat to get one with the spring.

I know the zj clutch was a band aid so to speak but I did it because I have a 180* thermostat and this is mainly a trail Jeep. It doesn’t see much road driving at all. I did it for the increased airflow when not going very fast through the woods. I have since changed that to an electric fan as I feel that was a better fit for this Jeep.

I will say to be honest I did not check the block for warpage. I had the head redone because it needed valve seals and I had assumed this was my overheating problem as well. The machine shop said the head was in good shape. He cleaned it up and said the head was not warped and put new valve seals in it along with a valve job.

Griffyorcono

Well than **** cause you'd think the block tester would come up with a problem if the block was warped. You're gonna have to go towards things that are much less obvious now. Start with checking the actual temperature of the motor with that ir gun you have, like you said previously though it seems like the temperature that the gun is showing is accurate to the temperature on your gauge. Your radiator could also be clogged so that needs to be looked at aswell, run some high pressure water through it and see if that helps at all. You could even run the Prestone flush once or twice.
If all else fails I wouldn't hesitate to take it to a well known Jeep shop that deals with this type of issue all the time.



Based on what you've said though the problem only occurs with the AC on so you need to get your heater core cleaned out, remove the hoses and run pressurized water through it.


Also last thing I forgot to ask did you properly burp the system, buy one of these and do it the right way just so we can get that out of the way. make sure you are squeezing the upper hose when burping it will help get that last bit of air out https://www.summitracing.com/parts/lil-24970?rrec=true

OldTires

Frankly, the cooling system has changed so much, it is hard to give advise on your situation now.

What caught my eye was that you wrote the Jeep was getting hot traveling on the highway with the AC on. At highway speed, the engine should have enough waterflow and airflow, to keep it cool. If not then, then I would suspect water pump or radiator performance. So how old is the water pump and radiator? What brand model is the radiator?

My Jeep was also getting hot with the AC on, but not at highway speed, only in stop and go traffic on hot days. I had screwed up years ago when I replaced the efan with a weak model. Once I replaced that fan with a higher quality, more powerful fan, my issues went away.

I am not sure how the new fan setup you have works and how much air it pulls, so that is now a big variable we can't answer. A picture would help to understand your new fan situation.

Griffyorcono

Finally someone who can also help, I feel like I'm just throwing the same ideas out that any ol basic jeep guy knows.... Thank you,