1998 Hitting 233 degrees

[Mudderoy]

As most of you know I've been fighting a running warm to down right hot Jeep for awhile now. Today's air temps were 88 degrees and I managed to hit 233 according to the OBDII scanner.

Driving between 50 and 60 mph it was running about 222, idle it would go up for a couple of minutes, then start to come back down.

From what I am seeing I think that I'm getting more air flow through the radiator at idle, or low speed than I am at over 40 mph.

I'm generating more heat moving the Jeep down the road I know so it could be that the coolant is getting hotter at 50 mph because the engine is generating more heat.

Here is what has been done;

1) Change of radiator, 3 times. Currently using a 2 row all aluminum Eagle radiator
2) Water pump less than a year old.
3) 160 degree thermostat, it was an experiment.
4) Replaced heater core
5) All hoses are a year or less old.
6) Grand Cherokee HD fan clutch, less than a year old.
7) AW4 has been disconnected from the radiator.
8) 4.0L Rebuilt, completely different engine including head and exhaust.
9) Sensors all replaced with Mopar parts
10) AW4 was rebuilt 1.5 years ago.
11) Catalytic converter replaced about 6 months ago along with muffler.
12) Radiator cap 16 psi (several of them)

The only thing in the engine bay that hasn't been replaced is the power steering pump and the master cylinder.

I still have a high flow water pump to put back on the engine, and I'll be going back with a 195 degree thermostat but I don't think that will help the 50 mph issue, although it might help it cool down at idle.

The only thing I can think of is air flow under and over instead of through the radiator.

So I think I'm going to fashion a 6" wide air damn just below my custom bumper.

Oh also I'll be putting the hood that has the cowl induction hood back on very soon.

Things that won't be happening.
1) Lights and winch removed from bumper.
2) Driving around without a hood.

[Mudderoy]

Oh I forgot to mention. I just let it get as hot as it wanted to. I was monitoring it. It didn't get any hotter than the 233.8 on the OBDII. Just before getting to the house, I turned off the A/C, no real change after 30 seconds to a minute. I then switched the control to vent, and turned the heat control full hot.

The coolant temp started dropping right away. 230, 226 and in less than 2 minutes pulling up in the drive way 217. I got out and checked the over flow to see if it was empty, nope it was really over full for the engine being hot.

But I don't think it was pushing coolant out on the ground. Could be, but I don't think so.

I got back in the Jeep to pull it in the garage and now the coolant temp was 213. So if I can figure a way to drive with the A/C and heater on at the same time I should be good. :mock:

[nickyg]

I feel your pain brother. I am yet to dance with the overheat goddess, but I am patiently waiting my turn.

[bluedragon436]

WOW... must be the power steering pump causing it then!! LOL... I am glad my overheating issue was taken care of by replacing the radiator... cause I def cannot afford the effort and parts you have tried to no avail!! Look forward to seeing if you find an answer to this issue... I know it isn't the lift height, as I am running 7.5" of lift and 33's and have had no issues with the exception of the hole in the radiator, with overheating!!

[Mudderoy]

Just checked the level in the radiator, full. Over flow is still were it was, as I remember it anyway.

Dunno. The air damn should be pretty cheap and easy to make.

[Carves]

............. So I think I'm going to fashion a 6" wide air damn just below my custom bumper.

Oh also I'll be putting the hood that has the cowl induction hood back on very soon ...............


As a suggestion ... Don't, do both at the same time.

Individual temp results for each - at various driving speeds/load conditions - would make handy reference info ... in one of your threads .. ;)

[Paddletrucker]

Tony, I've never had a problem with my Jeep, but I fought two years on a very similar problem on my semi. I'd replaced everything, or so I thought. It turned out that I had some "plaque" in some heater hoses and odd fittings. SOmetimes, it'd all break loose and clog something somewhere up. Everything was new. Coolant levels normal. I was going nuts.

I finally (out of anger) took off the radiator, water pump, ALL HOSES, heater core for cab and the heater core for sleeper, I found some 'crud' in a plastic elbow fitting that was mounted under the sleeper. I found more of it in other places.

I cleaned ALL fittings and all the nooks and crannies and replaced ALL the hoses with the blue silicone hoses. Removing the crud solved the problem. Is there a possibility of something clogging up the works on your Jeep in an out of the way place that you haven't found yet?

Just thinking out loud, I guess.

[Mudderoy]

Tony, I've never had a problem with my Jeep, but I fought two years on a very similar problem on my semi. I'd replaced everything, or so I thought. It turned out that I had some "plaque" in some heater hoses and odd fittings. SOmetimes, it'd all break loose and clog something somewhere up. Everything was new. Coolant levels normal. I was going nuts.

I finally (out of anger) took off the radiator, water pump, ALL HOSES, heater core for cab and the heater core for sleeper, I found some 'crud' in a plastic elbow fitting that was mounted under the sleeper. I found more of it in other places.

I cleaned ALL fittings and all the nooks and crannies and replaced ALL the hoses with the blue silicone hoses. Removing the crud solved the problem. Is there a possibility of something clogging up the works on your Jeep in an out of the way place that you haven't found yet?

Just thinking out loud, I guess.

I guess, but I can't think of where it would be. Especially after changing out the heater core. Remember this is a NEW engine.

[prerunner1982]

I know you say you won't be taking off the winch and the lights and I know you didn't have the heat problem with them on previously, but with everything else you have tried I would do it just to see what happens. If nothing else it will either point you in the right direction or have no change. But geez man, what haven't you replaced?

[Paddletrucker]

Gosh, with everything else you've done, I want to think its got to be something simple that's got away without notice. It's crazy and if it were me, I'd be going out of my mind.

The 160 degree thermostat. Is it possible that since its cooling at slower speeds, the coolant is circulating too easily under pressure and not spending enough time inside the radiator losing stored heat?? I know it doesn't sound right, but have you tried a HEAVIER than stock thermostat to slow the coolant down to give it more time in the radiator to radiate and lose heat so it goes back to the engine cooler?

Sounds crazy, though, to go heavier.


Sent from my iPhone using Tapatalk

[Brasscatz]

You listen to a lot of podcasts when you drive, right Tony? Maybe it's all that extra hot air! :D

[XJ Wheeler]

Sucks you're still battling this. What parts of the coolant system haven't you replaced, since this has started? I mean every tiny piece, no matter how small. Airflow could be an issue with all you have up there but i just can't see it being the whole story. MANY XJs have bumpers, lights, winch up there and no overheating.

This is my brothers '90. Not a lot of airflow either but his stays around 210°, it does have to use the efan to keep it under control but yours is overpowering the efan even still.

http://i1108.photobucket.com/albums/h401/xj-wheeler/Chris%20Jeeps/68329ee5d91214de8b01e593a709e686d4852090-1-1.jpg

[fovedollarones]

The 195 stock tstat as far as I've learned is at that temp for emmisions reasons as well as for your sensors to talk to your computer properly, which would affect performance and fuel mileage. Did you bleed the coolant system to get any air bubbles out? A bubble will cause the fluid not to move.

[Carves]

Gosh, with everything else you've done, I want to think its got to be something simple that's got away without notice. It's crazy and if it were me, I'd be going out of my mind.

The 160 degree thermostat. Is it possible that since its cooling at slower speeds, the coolant is circulating too easily under pressure and not spending enough time inside the radiator losing stored heat?? I know it doesn't sound right, but have you tried a HEAVIER than stock thermostat to slow the coolant down to give it more time in the radiator to radiate and lose heat so it goes back to the engine cooler?

Sounds crazy, though, to go heavier.


Sent from my iPhone using Tapatalk


The 160* t'stat is just letting the coolant flow to the radiator sooner.

If Ambients, Fan CFM, and the Heat Exchanging ability of a fitted radiator- are favourable ... Then, a 160* t'stat may provide a lower, constant, average, running temp.

In an XJ with a stockish system ... a 160* will "generally" just cause flip flop temp displays/readings - as it opens and closes ... depending on ambients.

My best results to date with a stockish cooling system ... is with using a 190* t'stat instead of a 195* ... The result is not much of a lower running temp - but the constant, average, running temp numbers, displayed on the digital gauges ... are much more stable.



Fitting a higher than a 195* temp t'stat - just means that the coolant is being bottled up in the, heat generating engine - for a longer period ... before its finally released to the radiator.

The radiator then has to have, an even better, heat exchanging ability ... to deal with the higher coolant temp it receives.



I dunno what Mudderoys issue is either ... With all the new bits in it - it should be as good as gold ??

Its common to point the finger at too much stuff blocking the grille ... but then - I dont have issues, even with the grasshopper catching, flyscreen stretched across the front of mine ??

One thing I would be doing if it was mine ... would be hooking up the dual probe, temp gauge I have ... to each end of the radiator ... and seeing just how much temp drop there is between the inlet and outlet ... in varying driving situations.

Another thing would be ... after fitting the airdam and before refitting the cowl hood ... Fit some spacers to the hood hinges and fit a larger firewall seal between the hinges ... allowing engine bay venting to occur at the hood rear corners - regardless of vehicle speed.

... and see if that made any difference.

[Mudderoy]

Thanks for the input guys, keep it coming.

Dual temp probe hmmm.

[bigjim350]

Mine was starting to run warm for a while. Went away when I removed the A/C condenser in front of the rad. Looked ok while looking at it in the jeep, but once removed i could hold it up in front of the sun and see just how clogged it really was.

[Mudderoy]

Thanks Jim, forgot about that one...

Here is what has been done;

1) Change of radiator, 3 times. Currently using a 2 row all aluminum Eagle radiator
2) Water pump less than a year old.
3) 160 degree thermostat, it was an experiment.
4) Replaced heater core
5) All hoses are a year or less old.
6) Grand Cherokee HD fan clutch, less than a year old.
7) AW4 has been disconnected from the radiator.
8) 4.0L Rebuilt, completely different engine including head and exhaust.
9) Sensors all replaced with Mopar parts
10) AW4 was rebuilt 1.5 years ago.
11) Catalytic converter replaced about 6 months ago along with muffler.
12) Radiator cap 16 psi (several of them)
13) Replaced A/C condenser

[89Laredo]

What do your fuel trims look like?

[msmoorenburg]

His fuel trims are like mine as I can tell via txting. I think you should try a stock tstat. the only items different from my jeep engine rebuild and yours is

1. mine stock tstat temp/stock radiator. His 160 and the nice radiator
2. mine stock cam. his is the stroker cam
3. I'm .030 over and he is .060 over

[gary63]

when you say the motor is new or rebiult is it the same block becouse you had the same problem before. You my have a peace of scale from the motor block stuck inside bloking some coolent .it my be around one of cyl. wall or up in the head. Sometimes you can take a infred hand thermomiter and run it over and around the motor and you may find a hot spot.That would give you a place to start looking.

[msmoorenburg]

when you say the motor is new or rebiult is it the same block becouse you had the same problem before. You my have a peace of scale from the motor block stuck inside bloking some coolent .it my be around one of cyl. wall or up in the head. Sometimes you can take a infred hand thermomiter and run it over and around the motor and you may find a hot spot.That would give you a place to start looking.

nope different block and head. They were hot tanked & cleaned by the same guy who did mine

[Mudderoy]

What do your fuel trims look like?

It varies all over, what am I looking for?

I saw it as low as -3% and as high as 9%

Long Term is usually 7%

[89Laredo]

That's different than my renix... lol
(Mine is a number between 0-256)
I'll see what I can find later.
Lean would make it run hot. New oxygen sensor?

[Mudderoy]

That's different than my renix... lol
(Mine is a number between 0-256)
I'll see what I can find later.
Lean would make it run hot. New oxygen sensor?

9) Sensors all replaced with Mopar parts

[89Laredo]

Manifold vacuum at hot idle?

[msmoorenburg]

Manifold vacuum at hot idle?

uhhh ya they all are, and i have the same 99+ intake he has and have monitored the temp in the manifold

[Mudderoy]

Manifold vacuum at hot idle?

15 psi cold almost 18 psi hot (if A/C is off)

[gary63]

nope different block and head. They were hot tanked & cleaned by the same guy who did mine

Hot tanking won't remove a piece of casting that may have come loose.I had that happen to me onetime. Changed everything twis fushed not it would get hot when running at high rpm like on the highway. took a therm. find one spot hotter than other in the same area.Then took a scope and looked in from a freezplug and got it out no more over heating.Not saying that is it but he had the same thing before the rebiuld.

[gary63]

sorry didn't see differnt block and head.

[msmoorenburg]

sorry didn't see differnt block and head.

no worries it was like i said hot tanked with new freeze plugs and blasted


looked like this (sorry no pics not painted)

http://i7.photobucket.com/albums/y299/msmoorenburg/IMG_20110904_181347.jpg (http://s7.photobucket.com/user/msmoorenburg/media/IMG_20110904_181347.jpg.html)

http://i7.photobucket.com/albums/y299/msmoorenburg/IMG_20110823_195314.jpg (http://s7.photobucket.com/user/msmoorenburg/media/IMG_20110823_195314.jpg.html)

[gary63]

I call a buddy who has a shop and he had a 2000 cherokee in with a running hot problem
and he check and replace everything. then he ask me to bring in my 2000 cherokee becouse I don't have a overheating problem.So he said he compered the 2 and he notesed some of the the components were moved and so he move everthing back. some he had to add wire and clips.and that is all.now that cherokee is not running hot.He did think that would do it and he is not a 100% sher that was the problem but that was the only different he did for the last overheat test to not overheating.some of the things were boxer fuse,controle,and hoses wire looms.

[Mudderoy]

I call a buddy who has a shop and he had a 2000 cherokee in with a running hot problem
and he check and replace everything. then he ask me to bring in my 2000 cherokee becouse I don't have a overheating problem.So he said he compered the 2 and he notesed some of the the components were moved and so he move everthing back. some he had to add wire and clips.and that is all.now that cherokee is not running hot.He did think that would do it and he is not a 100% sher that was the problem but that was the only different he did for the last overheat test to not overheating.some of the things were boxer fuse,controle,and hoses wire looms.

Hmmm I'm trying to process this. Are you saying that he put the wiring harness in the same position and the over heat problem went away?

[gary63]

Will from what he told me is he put the stuff back as it should be useing my jeep as a map.I geuss the wire looms were stritch across and the hoses were laying down into places that were open on mine.and the person move the fusebox and controle box so the
air could run were it was ment to.the way it was he said air would go thuogh the rad. and then down and no fresh air would get to the back of the motor to help in the cooling.witch then make the coolent do all the work.

[Mudderoy]

Will from what he told me is he put the stuff back as it should be useing my jeep as a map.I geuss the wire looms were stritch across and the hoses were laying down into places that were open on mine.and the person move the fusebox and controle box so the
air could run were it was ment to.the way it was he said air would go thuogh the rad. and then down and no fresh air would get to the back of the motor to help in the cooling.witch then make the coolent do all the work.

Wow that sounds like a mess! I have added extra wires, but they run from the under hood fuse box around the back of the firewall like the harness does. Everything else is in the same place. Interesting information though.

[gary63]

Ya I call him and ask for some more inf. .He said what he did is put some wireless camras
under the hood and put some cardbourd and ribin in diffrent places to see the air flowe.
What he found out was at a idel or slow driving upto 35mph the air moved around good
but when he got up to 50 and up the air movement from 1/2 way back to the back firewall the air was slowing down almost to a stop.He also said the hood was raised up alittle on the back and when he check it the air was being suck in I it should have been ether.So that was what got him checking other air movement.

[Mudderoy]

Ya I call him and ask for some more inf. .He said what he did is put some wireless camras
under the hood and put some cardbourd and ribin in diffrent places to see the air flowe.
What he found out was at a idel or slow driving upto 35mph the air moved around good
but when he got up to 50 and up the air movement from 1/2 way back to the back firewall the air was slowing down almost to a stop.He also said the hood was raised up alittle on the back and when he check it the air was being suck in I it should have been ether.So that was what got him checking other air movement.

Well I have a couple of Contour cameras that I can set up. I may do the same thing. I'll just have to figure out what I need to put in there to see what's going on, and where so it doesn't wind up wrapped around a fan! :D

[gary63]

he put the markers on and around thing like on the heater hoses one med.way and one close to the firewall.and on the other side on brake lines.He said you want at less 2 marking points.what he used was cardbourd that you can tape or clap onto things and then put ribon on it with tape or staples he used duct tape and staples.For lights he had lights but a under the hood light or small 12volt lights. And a 2nd person 1 to watch 1 to drive.He also said that this jeep had a trans.temp. gadge and he did notes the temp. was running a little cooler than before he started but that may have been something als he wasn't realy checking that.

[Mudderoy]

My morning run to work...

2192

[4.3LXJ]

Is it getting hot when the mixture leans down?

[Mudderoy]

Is it getting hot when the mixture leans down?

I'm still learning how to read the information, but it doesn't appear that way. I'll do another graph with upstream O2 voltage. I see the O2 voltage above .5 volts most of the time, so I don't think it's lean.

[Mudderoy]

With the coolant temp being 200+ and the upstream O2 voltage level being less than 1 I have scaled the O2 voltage by a factor of 100. So when you see the voltage on this graph it's .5 volts when the chart shows 50.

2194

There may be too much data shown here to be able to identify a lean condition. I may have to take a smaller sample during the time when the coolant temp is above 210. Mornings generally do not produce 210+ readings so this afternoons data collection may be better for this idea.

[89Laredo]

Looks like the mixture stays the same throughout, the engine temp just keeps rising...
I never have anyone to drive my jeep so I cant really keep an eye on my scanner and see what it looks like.

[Mudderoy]

Here is the run from work to home yesterday. Driving time about 45 minutes.

2196

2197

2198

[Brasscatz]

Looks like the mixture stays the same throughout, the engine temp just keeps rising...
I never have anyone to drive my jeep so I cant really keep an eye on my scanner and see what it looks like.

May sound odd, but if you don't have a way to record it, you can set up a video camera on the display and check it out after the fact

[89Laredo]

Big difference between 89 and 98 but maybe itll help. Here is a frame of mine. ~55mph, flat road, ~85* amb.



RPM-1444
O2(V)-4.22
INJ(MS)-10.8
LOOP-CLSD
EHAUST-LEAN
ST FUEL TRIM-137
LT FUEL TRIM-121
MAP SNSR(V)-3.2
MAP("HG)-21.3
MAN VAC ("HG)-8.6
BARO PRES("HG)-29.9
TPS(V)-1.43
THROTTLE(%)-29
THROTTLE SW-PARTIAL
FUEL SYNC +
COOLANT (*F)-191
CHARGE TEMP (*F)-129
SPARK ADV (*BTC)-35
KNOCK-8
BATTERY VOLTS-13.3Can you post a frame of yours? I still have ~120 frames saved on my scanner I can look through.

http://img.tapatalk.com/d/13/05/10/ebu8y2uh.jpg

[nickyg]

I have read this thread and reviewed all the information, I have a few possible causes that no one seemed to consider.

1 Global warming. (Curse you Al Gore)
2 Your town is built over an active volcano.
3 Some kind of voodoo curse. Try filling your radiator with chicken blood.
4 You have angered prestoneius , The Greek god of coolant. You must offer a sacrifice.

I don’t mean to make light of serious situation, Just figured you could use a laugh.

[Mudderoy]

Well the Mopar stock radiator arrived today...

2474 2475

2476 2477

2478 2479

2480 2481

[XJ Wheeler]

Lovely to see "Made in Mexico" on a Jeep part. :rolleyes:

[Mudderoy]

Lovely to see "Made in Mexico" on a Jeep part. :rolleyes:

I noticed that as well.

[cpttuna]

Just a suggestion: take those driving lights off the grill for a couple of weeks. Air flow might change???????????????????????

[Mudderoy]

Just a suggestion: take those driving lights off the grill for a couple of weeks. Air flow might change???????????????????????

Thanks, but no.

Here's the reason I think it would be a waste of my time.

http://offroadpassport.com/forum/showthread.php?t=402&page=50

[Carves]

Hope you have a win this time around .. :popcorn:

Removing the lights ought to be part of the trial and error process ... but fwiw it doesnt make a lot a difference in my experience ... as I dont see a lot of difference - even with the bug catcher screen on the front of mine.

[Mudderoy]

Hope you have a win this time around .. :popcorn:

Removing the lights ought to be part of the trial and error process ... but fwiw it doesnt make a lot a difference in my experience ... as I dont see a lot of difference - even with the bug catcher screen on the front of mine.

I had the problem before the bumpers, the winch and the lights. Several people have suggested taking the winch off and the lights. It's not the solution, although it could be part of the solution, a very small part, I'm not stripping my Jeep down so I can drive it. If I have to do that I'll just part it out and buy a TDI VW, a full sized truck or maybe a Wrangler with a normal sized radiator.

[nickyg]

If I have to do that I'll just part it out and buy a TDI VW

LOL.... I can't get the vision of out of my head of you squeezing into a VW. I hope the new rad works out. I'm pulling for ya.

[cpttuna]

Does it make any difference if you run straight antifreeze or something like a 60/40 mix?

[Mudderoy]

Does it make any difference if you run straight antifreeze or something like a 60/40 mix?

I haven't run any in a while, but straight water cools better than any anti-freeze. So more anti-freeze should make the problem worse.

[bigjim350]

Just grab your credit card and order this.....hell it might even work.
http://www.rustysoffroad.com/jeep-performance-parts-products/advance-adapters-engine-swap-radiators/flex-a-lite-direct-fit-radiator-w-electric-fans-xj.html

[Brasscatz]

Just grab your credit card and order this.....hell it might even work.
http://www.rustysoffroad.com/jeep-performance-parts-products/advance-adapters-engine-swap-radiators/flex-a-lite-direct-fit-radiator-w-electric-fans-xj.html

holy canoli... I would LOVE to give that thing a shot, but for 1/10 the price!

[Mudderoy]

holy canoli... I would LOVE to give that thing a shot, but for 1/10 the price!

Rusty's advertises on Powerblock, gotta make the money back some how. They won't make it from me though.

[XJ Wheeler]

Says it gives 2,400 cfm too. :banghead:

[gary63]

griffin has one too it is over 1000 the may not run hot but that is because no money for gas.

[gary63]

hay I was looking at your bumper again I know you had a heat problem before
did you have the airdam on the bottom of the old bumper? If not have you tried covering up the holes on the bottom just to redrict the air.
Just this weekend a friend broke his off and it started to run hot he put a nother one on that he had and it is running cooler again.

[Mudderoy]

hay I was looking at your bumper again I know you had a heat problem before
did you have the airdam on the bottom of the old bumper? If not have you tried covering up the holes on the bottom just to redrict the air.
Just this weekend a friend broke his off and it started to run hot he put a nother one on that he had and it is running cooler again.

On the 97+ the air dam is part of the bumper. I guess you could still have a problem with it, but no bumper was intact until I took it off to install this DETOURS custom.

I have looked into buying some hard, but flexible plastic and making an air dam, which I may still

[Mudderoy]

This radiator doesn't have the bolts to put the rubber tie down. It had slots for something to go in there. I took some bolts that I had and ground down the heads to they'd fit.

Then I found this radiator doesn't have the condenser supports, but as you can see the condenser rests on the front of the radiator edge, leaving a good space between the condenser and the radiator. I may try to fashion up some supports in the next week or so.

2524

2525

2526

[nickxj94]

I just installed a cheap Oreally radiator for my 2000 it seems to run cooler right now but its only been in 1 day I put 50 miles on it so far running the AC, I have no air dam or fan shroud on mine it stays about 210

[89Laredo]

I still think it's pretty weird that you are having these problems... mine has a Napa radiator for a 97 in it, 195 thermostat, and hd fan clutch, almost never goes over 200 even in 100* amb...

[Mudderoy]

I still think it's pretty weird that you are having these problems... mine has a Napa radiator for a 97 in it, 195 thermostat, and hd fan clutch, almost never goes over 200 even in 100* amb...

I'm beginning to wonder if it's a 97+ issue.

[89Laredo]

That's what I was thinking too.
Could your condenser be icing up and blocking flow? I'm assuming you run ac almost constantly?

[Mudderoy]

That's what I was thinking too.
Could your condenser be icing up and blocking flow? I'm assuming you run ac almost constantly?

Even with A/C off it runs about 220's (213 to 226)

[msmoorenburg]

Even with A/C off it runs about 220's (213 to 226)

all i'm gonna say is :thumbsup:

[Mudderoy]

Test day 1. About 12 miles into my 19 mile trip home. 90 degree air temp, bright and sunny, A/C on.

2538

High coolant temp was 215 that occurred after accelerating on 529 about a mile then coming to a stop.

Dropped to 208 within about 15 seconds of leaving the intersection after the light turned green.

[Brasscatz]

hmmm.... so far so good

[Mudderoy]

Quick and dirty graph of today's coolant temps.
The straight line thru the data is a trend line. What looks different here is the over all temp range is much narrower than before.

Again this is with A/C on, 90 degree air temps, sunny day. Average speed was about 33 mpg.

2539

Also a 195 thermostat had been installed a few weeks ago, which is why the early temps are higher. A 160 degree thermostat was what was in it prior.

[nickxj94]

I think your cooling problems came up here and bit my 94 xj! Mine has been running warm for two weeks now only at highway speeds and pulling hills. If I'm trail running or idle it never goes above 210 when I'm driving 55+ it gets about 220-230 pulling hills pegs out at 240-260 but cools back down once I let off the gas going back down the hill or pulling over. I have a 180 tstat,new water pump, new belt, and coolant, and this is with air off or on it don't matter..

[Mudderoy]

I think your cooling problems came up here and bit my 94 xj! Mine has been running warm for two weeks now only at highway speeds and pulling hills. If I'm trail running or idle it never goes above 210 when I'm driving 55+ it gets about 220-230 pulling hills pegs out at 240-260 but cools back down once I let off the gas going back down the hill or pulling over. I have a 180 tstat,new water pump, new belt, and coolant, and this is with air off or on it don't matter..

When was the last time you replaced the radiator.

[nickxj94]

When was the last time you replaced the radiator.

Never LOL

[Mudderoy]

Never LOL

http://www.factorymoparparts.com/05191929aa.html $127.65 plus shipping. I think I paid about $140(ish)

[nickxj94]

http://www.factorymoparparts.com/05191929aa.html $127.65 plus shipping. I think I paid about $140(ish)

So guess I need a radiator?

[XJ Wheeler]

pegs out at 240-260

Lol, don't do that!

[nickxj94]

Lol, don't do that!

I know that hot tends to blow headgasket, that's why I pulled over and let it cool off with the fans

[XJ Wheeler]

I know that hot tends to blow headgasket, that's why I pulled over and let it cool off with the fans

Personally, i wouldn't let it get over 240 before pulling over. 260 is pretty dangerous. And i wonder what your trans temp is if you're engine is that and you're pulling up hills. Do you have a cooler or gauge?

[Mudderoy]

So guess I need a radiator?

Well a guy here in Houston in charge of the city fleet said that any time the Cherokee would start overheating he'd replace the radiator. At least that is what I was told by a 2nd party.

You've already changed everything else, well I don't remember if you said fan clutch or not.

Certainly a radiator won't hurt, as long as you get the right one. ;)

[nickxj94]

Personally, i wouldn't let it get over 240 before pulling over. 260 is pretty dangerous. And i wonder what your trans temp is if you're engine is that and you're pulling up hills. Do you have a cooler or gauge?

I have a external
cooler.
I pulled over when it got 240





Well a guy here in Houston in charge of the city fleet said that any time the Cherokee would start overheating he'd replace the radiator. At least that is what I was told by a 2nd party.

You've already changed everything else, well I don't remember if you said fan clutch or not.

Certainly a radiator won't hurt, as long as you get the right one. ;)

[Mudderoy]

Yesterday we had a team outing and since we were out well before traffic time I decided to take the 98 on a highway test.

I drove 33 miles highway, most of it was at highway speeds.

2953

231.8 was the max temp

[Mudderoy]

If anyone is keeping score... not sure what that means...

The heavy duty radiator that my 1998 Jeep Cherokee came with from the factory (according to a dealer) was Mopar 52080104ac

$253 plus shipping from Factory Mopar. :link: (http://www.factorymoparparts.com/52080104ac.html)

[reddragon72]

Tony,

My 94 had horrid issues with temps. I got tired of battling it and headed to LQK and ripped a radiator out of one of their wrecks. Cost me about 40 bucks plus core.

I can honestly say that there was 50 pounds of difference between the two and the bad thing was that the old one flowed and seem to flow ok at street speeds.

What happens is if you have a clogged radiator then you will over heat on the freeway due to higher RPM's. The higher RPM's and a clogged system causes the pump to cavitate. When this cavitation happens the pump will only provide 1/10th of it's pumping power and will backflow hotter coolant so in essence it is pushing some hot coolant back into the engine.

My jeep has not had one issue since I replaced the radiator with a junk yard one.

Now if you have already done this then my other idea is for you to open your hood and remove the rubber strip along the back firewall that seals the hood and drive it like that on the freeway. If that works then you are generating a suction in the engine bay at freeway speeds. This could be from the custom bumper or from the height of the rig and front axle. removing that rubber seal will help break that vacuum.

give either a try and see if it helps. The seal may only drop your temps 10-20 degrees as it will not clear the issue completely due to the small space the seal occupies but it will give you an idea.

[nickxj94]

Have you tried straight water and water wetter? I changed over and mine has done alot better staying 185-210 depending on outside temps.

[Mudderoy]

I recently put the stock front skid plate back on the 98 at Matt's recommendation. I "thought" I saw some coolant temp improvements, but nothing that I couldn't say was just wishful thinking. What I needed was a sustained highway speeds drive. Now that we're in September the summer heat "testing" temps will soon be changing.

Yesterday I had a late afternoon doctor's appointment, so it was my chance to do a highway run back to Katy and test out the new configuration.

Remember it takes about 12 miles for the coolant temp to rise above 210 normally.

I got on 249 and put it on 70 mph. With my 4.56 gears, 33" tires and AW4 transmission that translates to about 2,500 rpm. About the 12 mile mark I hit 215. About 20 miles it was 217. I did see a brief 221 after some heavy acceleration, but it settled back down to 219/217. 65 mph seemed to cool better than 70 mph.

The air temps (according to my smart phone and the weather service) was 95 degrees. It was a combination of sunny and cloudy. I certainly could tell the difference with the sunny, although the effect was minor maybe 2 degrees.

So I'm pretty happy. Actually the coolant temp was higher driving from the doctor's office to my home. I wasn't going as fast, so 220's is where it was sitting.

I may try to extend the skid out to the sides in an attempt to increase air flow through the radiator at highway speeds. Also I may install the FlowKooler water pump and see if I can get the low speed temps down, without hurting the high speed temps.

[Dredwolf]

I'll add in about making sure your fan shrouding works right.

I had to trim the fan shroud on the '03 Explorer to accommodate the body lift, only about 1.5" at the bottom of the arc.

But you can tell the difference in idling temps in traffic, so over the winter, I am going to fab up some aluminum sheet to "channel" the altered airflow so the fan can better do its job.

[hawkmantn]

Tony, I've been following your highway overheating adventure on xjtalkshow and finally decided to join as it sounds like i am having about the same issue with my 98 xj after replacing the stock radiator(non max cool) and water pump last fall...

Are the results you posted on Sept 6 from the Mopar 05191929AA you installed?

I am considering trying the 52080104AC which is supposed to be the factory aluminum and plastic tank max cool for 98-01...

Sent from my Galaxy Nexus using Tapatalk 4

[Mudderoy]

Tony, I've been following your highway overheating adventure on xjtalkshow and finally decided to join as it sounds like i am having about the same issue with my 98 xj after replacing the stock radiator(non max cool) and water pump last fall...

Are the results you posted on Sept 6 from the Mopar 05191929AA you installed?

I am considering trying the 52080104AC which is supposed to be the factory aluminum and plastic tank max cool for 98-01...

Sent from my Galaxy Nexus using Tapatalk 4

Thanks for listening to the show. The September 6th information is the 52080104ac dual row heavy duty factory Mopar radiator that came with my 1998 XJ, Up Country and towing package.

I can't be certain if the semi-positive results on my last highway test are due to the radiator, the factory front skid, or both. At this point I just want to be able to drive on the damn highway again! :bacondance:

[redneck999]

Question! Have you tried any testing without the hood completely? If it got better that would prove the problem in the hood still restricting the escape of heat. I have had a cobra jet scoop reversed on mine for about 2 yrs and am considering putting on a long louvered panel on the hood just behind the radiator and using the same type of rivet on panels on the fenders close to the firewall or so to give more opportunities to vent. trying to explore options maybe not used yet.

[cpttuna]

I do not see it mentioned but what brand of coolant and what kind of mix are you running?? Have you varied it at all??

[SteveMongr]

The V8 Grand fan clutch solved all my issues. Now I can run in deep sand at 210. Or idle with AC on and the temp stays at 210. The factory gauge reads 200.

[Mudderoy]

Question! Have you tried any testing without the hood completely? If it got better that would prove the problem in the hood still restricting the escape of heat. I have had a cobra jet scoop reversed on mine for about 2 yrs and am considering putting on a long louvered panel on the hood just behind the radiator and using the same type of rivet on panels on the fenders close to the firewall or so to give more opportunities to vent. trying to explore options maybe not used yet.

No but I do have a hood with a cowl induction scoop. It takes 12 miles for the coolant to heat up, I'm not driving around without a hood, especially for 12 miles. ;)

:link: (http://www.xjtalk.com/showthread.php?t=6313)

[Mudderoy]

I do not see it mentioned but what brand of coolant and what kind of mix are you running?? Have you varied it at all??

Nothing cools better than straight water. Until I got done changing things I wasn't going to put any coolant additives in it, since it was just going to get poured out on the ground. I have Preston in it now, no idea what the mix it. It's in there mainly to stop the rust. In Houston we don't need coolant except maybe every 15 to 20 years.

[Mudderoy]

The V8 Grand fan clutch solved all my issues. Now I can run in deep sand at 210. Or idle with AC on and the temp stays at 210. The factory gauge reads 200.

I've run one for years. Recently took it off and put a stock fan clutch back on it. It may have made a 2 to 3 degree difference in temperature. Not worth the noise and additional horse power.

The hood with the cowl induction scoop I have will solve the off road low speed heating issues, I just got to get my ass in the garage, bond, sand and paint it.

[gary63]

Nothing cools better than straight water. Until I got done changing things I wasn't going to put any coolant additives in it, since it was just going to get poured out on the ground. I have Preston in it now, no idea what the mix it. It's in there mainly to stop the rust. In Houston we don't need coolant except maybe every 15 to 20 years.

on coolant you should be using 50/50 if you are running 100% Preston or any coolant it will not work right the cooling and heating will be off. it will run hotter and in cold weather it will thiken up. As for straight water it work good but additive will help it cool even better. Also the additive help the running temp. it will even the heat out so the motor runs at more even temp. through out the block.

[hawkmantn]

Thanks for listening to the show. The September 6th information is the 52080104ac dual row heavy duty factory Mopar radiator that came with my 1998 XJ, Up Country and towing package.

I can't be certain if the semi-positive results on my last highway test are due to the radiator, the factory front skid, or both. At this point I just want to be able to drive on the damn highway again! :bacondance:

Well, I just installed the Mopar 52080104AC last night. So far I haven't seen the temp get above 207 at highway speeds! - I took it out for a night drive for about 30min at highway speeds 65-75mph. I'll be watching it closely, unfortunately I didn't install it during the peak summer temps and so all I have to go on is that it was overheating up to 230 (scan gauge) above 55mph even when it was dark.

The best sign that I have seen is that either an increase in engine rpm or wind speed NOW results in the temp decreasing as opposed to its previous slow climbing with higher rpms and speeds above 50. Again I have only driven it 30min last night when it was about 70degrees here in TN, and then again this morning for 15min on the way to work. Its looking good so far, but I still want to be sure! Thanks for the tip on the Mopar part number! I'll post again after I give it a chance to prove itself to me :)

Sent from my Galaxy Nexus using Tapatalk 4

[Mudderoy]

Well, I just installed the Mopar 52080104AC last night. So far I haven't seen the temp get above 207 at highway speeds! - I took it out for a night drive for about 30min at highway speeds 65-75mph. I'll be watching it closely, unfortunately I didn't install it during the peak summer temps and so all I have to go on is that it was overheating up to 230 (scan gauge) above 55mph even when it was dark.

The best sign that I have seen is that either an increase in engine rpm or wind speed NOW results in the temp decreasing as opposed to its previous slow climbing with higher rpms and speeds above 50. Again I have only driven it 30min last night when it was about 70degrees here in TN, and then again this morning for 15min on the way to work. Its looking good so far, but I still want to be sure! Thanks for the tip on the Mopar part number! I'll post again after I give it a chance to prove itself to me :)

Sent from my Galaxy Nexus using Tapatalk 4

I think what I have learned over the long costly time working on this issue is the two things I was told many years ago when I first attacked this problem.

1) Always buy factory parts, sensors for example, and clearly the radiator in the case of the Jeep Cherokee.

2) Don't make the over heating problem, find and fix the issue. My issue was a leaking heater core. I wanted to work on, upgrade or replace everything else and not NOT remove the dash to replace the heater core.

After the heater core was replaced the cooling system still hit 230's but it stopped there! Then it would cool off. Also it helped with Matt having a 1997 XJ, new motor etc... and while his temps were a little lower his cooling system displayed the almost identical symptoms.

Conclusion? It's doing what it's supposed to do.

[redneck999]

I'm still waiting on a response from dirt bound off road about the triple fans, now they are adding an option of having spal fans but no price yet. FFD is selling their kit on ebay for 335.00 Or i order just the fan shroud from db and get the spal fans 80. ea and a wiring kit 150. from summit. Iv'e been keep ing an eye out on facebook for dirt bound.