overheating (Kinda long)

[Dingo509]

Before i get yelled at for this let me give you a history:

91 XJ 4dr. 233K 4.0 aw4 with a/c
In order of install per item
2 Radiators a stock 2 core and currently a gdi 3 core
3 water pumps 1 mopar, 1 cheap rebuilt, currently new aftermarket
6 thermostats mopar, 4 aftermarket 2@180, 2@ 195, currently mopar
2 heater valves, both mopar
2 t-stat housings both mopar, currently hand ported
all hoses have replaced at least twice

Fan setup went from stock electric and mechanical to dual electric (1 stock 1 flex-a-lite 110) to dual flex-a-lite 110

Other mods 99+ intake swap, 60mm throttle body, donaldson airbox rated at 350 cfm, 98 5.2L durango injectors

I have pulled the head and it checked and machined flat (.007 max is .006)
I can drive it just fine if the temperature is below 60 otherwise it overheats
Mainly on the freeway, i can sit idle in traffic at over 100 ambient and it runs below 200 all day. it also overheats very fast when pulling steep grades, at any speed or ambient temperature.

Ive been fighting this for 3 yrs. now and basically can't drive it in the summer.
Any ideas?

Dingo

[Dr. Dyno]

Since your engine overheats on the highway and when climbing steep grades, the first thing I would think of is a clogged radiator. The problem is, you've already replaced it so I'm inclined to think of something that's not related to the cooling system itself i.e. engine running too lean under load.
Your injectors are probably a bit marginal since they only flow 20.8lb/hr at 39psi. I suggest you build a MAP adjuster and increase the MAP voltage above the stock 5.0v to hold the injectors open longer and richen things up a bit. It's a cheap fix and it might just work:

http://www.angelfire.com/my/fan/MAP_adjuster.html

[Sarge]

You don't specify what you mean by overheating. I only ask cause I've seen folks here claim their XJ is overheating when it was 210 or a wee bit over that. Is it boiling over? Hitting the red zone? The Dr is probably on the right track as it seems to happen under load.

Sarge

[RichP]

Just an aside here because of the electrics. The fan shroud is often overlooked as a really necessary item. The fan pulls air in thru the rad, the reason the fan is set back where it is makes sense if you think about it. The fan creates a vacumn inside the fan shroud, this pulls air evenly thru ALL the fins on the radiator. The mechanical fan handles about 50% of the fan square inches, top to bottom on one side of the rad, the electric side is not normally cooled by a fan pulling air, as the temp goes up and triggers the electric that covers the other 50% of the rads surface. The factory electric is not the most efficient due to its closeness to the rad surface but moving it futher away might even out the flow and pull more air over the areas it does not cover.
All the electrics I have seen sit either a hairs breadth or a 1/2 inch away from the radiator and leaves alot of the radiator not covered which creates hot spots in the rad itself. Most of those aftermarket fan shrouds do not cover and seal the rad surface like the factory shrouds.
Realistically the factory mech fan and clutch are really not running at hiway speeds, the mechanical is more or less moving air out of the way of the incoming air at hiway speeds.
The lean condition is a possiblity and should be looked at, the other thing I would do is put a 7 hour flush in there to remove scale from the passages, the scale that builds up from using normal tap water over time can and will act as an insulator so that you might not be getting enough heat transfer as the coolant flows thru the block.
I've seen this happen before, back in my navy days on the subs we used to make our own air and fresh water with sea water thru a distiller plant, we had to de-scale the flask on a regular basis and the stuff that came out of seawater was amazing when processing 500 gallons a day.
Just some ideas...

[Planetcat]

I replaced all the same things you did but not as many times, ran one flex a lite 110 + OEM electric fan, still overheated. I concluded (no proof though) that the 3-row rad (new Modine) didn't work for my setup because I had both the AC compressor and tranny cooler in front of it. By the time the air hit the 2nd and 3rd rows of the rad, it was already warm. So essentially, I thought it performed like a 1-row with very small diameter tubes. I installed a 1-row aluminum radiator (http://www.alumrad.com) with very large tubes and ripped out the flex a lite fan, replaced fan clutch with a fixed spacer from summit racing, and added water wetter. Now I can tow my 3200# boat in 100* temps all day long without even getting over 210*. The aluminum rad was something like $150 and fit like a glove. You might want to do the scaling flush first, 'cause you're probably sick of replacing parts. I also did hp mods thinking that would help, but it didn't. Before that, it boiled over constantly and soared engine temps to 260*. I dont' think the water wetter helped, but I like Redline products.

[Dingo509]

As far as defining overheating if i pull a continuous grade for like 5 mins it will boil over. if i let it i usually pull over pop the hood and let it run for a while then it will cool down and i can continue.

I have built a map adjuster however i have not had time to install it yet.
Dr. Dyno you said the injectors flow 20.8@39 psi is that the stock injectors or the 5.2 injectors?

As far as the electric fans go the Model 110 is a 12 fan mounted in a square "15"x13.5" i think" shroud with weatherstrip around the edge to seal it to the radiator. as the rad core is 31" x 11" i fabbed a aluminum bracket both top and bottom of the rad to help "seal" the fans to the radiator.

I really appreciate all your help so far. And i hope i don't sound like an unthankful ass from this last post but i need all the help i can get and if that means you need more info so be it.

Thanks again
Dingo

[Dr. Dyno]

As far as defining overheating if i pull a continuous grade for like 5 mins it will boil over. if i let it i usually pull over pop the hood and let it run for a while then it will cool down and i can continue.

I have built a map adjuster however i have not had time to install it yet.
Dr. Dyno you said the injectors flow 20.8@39 psi is that the stock injectors or the 5.2 injectors?


That's for the 5.2 injectors. The stock '91-'95 4.0 injectors flow 21.0@39psi so they're almost the same. The thing is, you've increased airflow to your engine with mods so it could now be running lean.
You said the coolant boils over. If the pressure cap on the radiator is working properly, the coolant should only boil over if its temp. reaches 250+*F. If your gauge isn't in the red when it boils over, you need to replace the radiator cap.

[trashedxj]

ok it sound really dumb but heres a temperary fix(ie fixes the prob. for a short time) i had a celica over heat all the time and the other day for the first time ever my xj was extending the red zone, (i.e. if this is the temp guage cold. . . . .mid. . . . .RED this was mine . .RED. . . . bout here! heres what i do when the temp goes bout mid way from mid to red i turn the heat on full blast!!! hey it works!! oh and i gotts a magazine bout heat, the xj because of the way the inline's are they produce more heat than most racing v8's!!! i recommend hood louvers aint that mush, a nice set is bout 100-150 bucks and cut the holes in the hood drill little ones around it and pop rivet the louvers on then just paint the hood again to the same color!!! louvers according to the studys in my mag reduce the overall heat my as much as 37 degrees at some spots(temp readings were taken from 15 places while engine was running!!!

[rsalemi]

I would go with the "too lean" condition producing more heat than the cooling system can handle. Because it can run at low speeds without overheating (where most XJ's have a problem) its not cooling system related.
Either go to larger injectors - 24# mustang or 53030262 MOPAR (95 ZJ?) or turn the map adjuster up to 5.5 volts and test it - running with more fuel should solve the problem - then invest in the larger injectors.

[boise49ers]

I had a similar problem for about 2 years and found after changing all the above that the little hose that comes out of the bottom of the tank(closed system) That hose was clogged at about 80 percent not letting the coolant circulate very well. Also check your clutch on your fan. If it is hot turn it off, if the fan turns by hand the clutch is bad and it isn't working to draw air at hi-speeds or RPMs.
Good Luck I know it is a Pain dealing with Cooling problems.

[Dingo509]

i've been thinking about the lean condition too
i thought the 5.2 injectors were bigger whoops!
I have got tholes cut in the hood and have run with the heater on. at about 90 ambient with the heater on full i can run about 20 mins before it's in the red.

With the 99 intake, the bored T/B and the borla header is that really enough to make it overheat that bad?
I pretty good at fixing stuff but i got half the shops in town puzzled too.

Thanks again i'll try and install the MAP adjuster this weekend and let everyone know what happens.

Dingo

[blaisetd]

Not sure if your jeep has the same cooling system as mine, a closed system, but converted it to open. I found this article and it worked great.
http://www.madxj.com/MADXJ/technical/technicalfiles/JTopenSystemSwitch/OpenSystemSwitch.htm

'90 XJ 4.0 auto trans

[jeepsrock]

I would get rid of the electric fan and put in a replacement fan clutch...that seems to work the best on these engines. Additionally i would convert it to an open system if its currently closed.

pete

[Dingo509]

update......

The system is closed but i am thinking about relocating the rad cap to the upper hose as this (in my system) is higher than the stock cap location on the radiator.

As far as it being to lean, i just got back from a test drive with stock 91 injectors. and the autometer ait/fuel ratio gauge. I noticed absolutely no difference with either of the injectors, and the gauge confirmed it. however the guage does occasionally dip into the severe lean condition and then stays there for almost a full second. but it does this only at steady road speeds, not when pulling a hill, where it reads stoich or slightly rich. as far as temp goes, with a 6 minute climb up a local road it had reached about 240 degrees. as soon as i come back down it cooled back down. This with an ambient of about 45 degrees. So i believe the cooling system is okay and it has to do with the injection system. But Im out of ideas. again. Am i still runnning to lean and the air/fuel gauge just a purdy light display or there something maybe im still missing.

Thanks
Dingo

[canadian-xj]

the autometer a/f gauge is nothing more than a pretty light show. It also will only read when u load the motor at wide open throttle. Most efi vechiles also ingore the 02's at wot. I would do a dyno pull to get correct a/f readings.

[themud]

i've been thinking about the lean condition too
i thought the 5.2 injectors were bigger whoops!
I have got tholes cut in the hood and have run with the heater on. at about 90 ambient with the heater on full i can run about 20 mins before it's in the red.

With the 99 intake, the bored T/B and the borla header is that really enough to make it overheat that bad?
I pretty good at fixing stuff but i got half the shops in town puzzled too.

Thanks again i'll try and install the MAP adjuster this weekend and let everyone know what happens.

Dingo

Hey thats what I did to mine k&n fipk with bored tbody headers and exhaust I could stand on it here in AZ from stoplight to stoplight and watch it shoot up at least 20-30* and freeway driving was much higher...super lean is the best way to describe whats happening to you I picked up hescos adj fuel pressure reg and it helped a whole hell of a lot...Now my only problem is getting the damn thing started it cranks and cranks and then catches and just kind of sputters for a sec or two the idles fine just like nothing happened...I might have either a vaccum leak(I didnt put a new gasket on when I changed the intake) or my fuel pump might be going on me...You could try the map adj first (its cheaper by far) put the stock injectors back in theyll be fine I had mine tested matched and cleaned they also ran them up to 65 psi and checked flow and they were still good...Ya just need more fuel its too damn lean...If you pick up this months jp the did the story on power upgrades and had the same problem as you...
luck
themud

[Dingo509]

Is there any vehicles that run 24# injectors stock? i was thinking about finding a set in a wrecking yard just to confirm the lean condition then buy a new set later.

Dingo

[FUNKYTEE5]

Is there any vehicles that run 24# injectors stock? i was thinking about finding a set in a wrecking yard just to confirm the lean condition then buy a new set later.

Dingo

All Ford 460's have 24's I think the SHO Taurus motor has them too?

[Gojeep]

You have a bad choice for fans there with the 110's. They only pull 1250 CFM which is not nearly enough. Should be at least 2000 CFM along with a 97+ stock electric to make it work. See my site for the write up. I run this combo in the Outback towing across deserts in deep sand with 100*F temps no problem at all. Just did another conversion for someone today and doing another next weeks as well for another as they work so well.
www.go.jeep-xj.info

[Dingo509]

got to thinking ( i know i shouldn't do that) but is it possible for the timing to change and the engine still run?

Dingo

[Dingo509]

ok installed the map adjuster, and removed the vacuum line going to the fuel pressure regulator, yes i capped the vacuum port. i also found the stock injectors and swapped them back in. i then set the map adjuster to 5.3 volts with the fuel pressure at 40 psi (autometer procomp mechanical guage). trying to get it to run rich. i didn't change anything it still gets just as hot just as fast.

so 2 more ideas. what should the fuel pressure be without the regulator hooked up?
and (long shot) but if i understand the map sensor adjuster correctly it only works in open loop operation correct? If the computer operates in closed loop operation then the adjuster does basically nothing. so could you use the same basic concept (and maybe parts) the build and o2 sensor adjuster? i think the o2 sensor only gets 1 volt instead of 5 but if you could change parts a little you should, in theory, be able to adjust the o2 sensor voltage so it will lean or richen the mixture in closed loop mode.

I think.

Dingo

[JungleXJ]

You could hook up one of those aquarium air valve adjusters that you get from pet shops. That way you can adjust the vacumn, costs next to nothing.

[rsalemi]

You can adjust the fuel pressure to 46 lbs or so and/or set the MAP to 5.8V to get more fuel in there. My 4.0 with K&N and Borla made the most HP (189 at rear wheels) with 48# pressure on the stock injectors. In tuning - you need to make big steps to see results - then back down to refine it.

[CRASH]

Just for comparison. I have a Renix based 4.6 stroker, very open intake, header, 2.5" mandrel bent exhaust. I use 24 pound injectors, and it runs dead smack at 14.7 to 1 on the highway. The adjustable MAP does nothing for you under light throttle, it only works under WOT, when the computer is ignoring the o2 sensor. In fact, I pulled my adjustable MAP out because A) it failed under off-road conditions and B) I had it set up at 5.0 volts, same as factory. Under WOT, at 5.0 volts, I run 13.2 to 1.

All readings are with a 5 wire Bosch wide-band O2 sensor and digital guage.

As a note, it takes more than you might think to get the engine to drop into WOT mode. At least 2 seconds of foot-to-the-floor on a steep grade and it will finally drop down to 13.2 or so.

I don't think running lean is your problem. I had the EXACT SAME condition as you, and I fixed it with a new 2 core Modine radiator (there is no such thing as a three core Modine, contrary to info in this thread).

Edit: See this thread : http://www.naxja.org/forum/showthread.php?t=43966

CRASH

[rockwerks]

Just a few thoughts here I dont think his problem is a lean one I think it is a gearing, auto trans problem

what gearing are you running and what tire size, or is it all stock?

I ran 33's and 3:54 gears and had the same problem, not a hill friendly setup the trans was overheating due to the tire gear ratio problem, I fixed it by removing the tranny cooler lines from the radiator and putting in a seperate trans oil cooler and fan with adjustable thermostat that came on at 180* never had any more problems

also dont forget you can put on the heater and the temp goes down not too comfortable for the summer but it does stop the overheating

[Dingo509]

<< You can adjust the fuel pressure to 46 lbs or so and/or set the MAP to 5.8V to get more fuel in there >>

Can the fuel pressure be adjuster somehow without buying an adjustable fuel pressure regulator?


<< I don't think running lean is your problem. I had the EXACT SAME condition as you, and I fixed it with a new 2 core Modine radiator (there is no such thing as a three core Modine, contrary to info in this thread). >>

In the original post i listed all the cooling mods, i have run 2 radiators (stock 91 HD and now a GDI 3-core) no change at all. I have had the GDI pulled apart and cleaned like 3 times so far too.


<< what gearing are you running and what tire size, or is it all stock? >>

33x12.50 Superswamper SSR's on 15x10 Trailready Beadlocks.
D44 front, full float D60 rear, with 4.56 gears. 4 wheel disc and ARB's

The tires/gears/axles/brakes etc. where on before the overheating started i did however change the Wheels. they where some cheap lightweight aluminum 15x10's the trailreadys have steel centers.


<< also dont forget you can put on the heater and the temp goes down not too comfortable for the summer but it does stop the overheating >>

Actually I did run with the heater on in 100 deg temps on the freeway and it didn't help much i could go about 40 miles starting with a cold engine before it would boil over.

Last night i tryed setting the map adjuster to 6.0 volts and the check engine light came on; code 14 map sensor voltage. how high can you run it without it throwing a code?

I hope i don't sound like an ass answering all these questions so short. I really appreciate all the ideas and i know with everyones help we can get this XJ to run cool again. (well at least as cool as you can an XJ)

Did anyone catch the post on possible making a 02 sensor adjuster?

Thank you and keep the ideas coming.

Dingo

[CRASH]

The GDI's have notoriously poor build quality, sometimes 30% of the tubes are occluded. Cleaning it does nothing ot help this problem. My GDI ran fine on the trail, but overheated on any long climbs. The Modine fixed the problem.

Is it overheating only at WOT or under cruise conditions? Your computer may not be dropping into WOT mode for a variety of reasons, making it run hot when you are in the throttle for extended periods.

You can enrich your mixture in various ways. If you bump your fuel pressure, it will fatten evything up across the board. But remember, your O2 sensor is fighting these efforts when the enigine is in closed loop mode. It wants you to run 14.7 to 1, so it will do all it can to fend off the extra fuel, within it's mapping. Once you exceed its mapping parameters, it will throw a code. The only time the enrichment efforts help are when you are in open loop mode, at start-up and under WOT.

In your specific case, you don not have nearly enough mods to be out of the OEM mapping parameters, so don't sweat it. If anything, you are having a malfunction of one component or another, not allowing the computer to drop into open loop mode.

What are your trans temps like?

CRASH


<< You can adjust the fuel pressure to 46 lbs or so and/or set the MAP to 5.8V to get more fuel in there >>

Can the fuel pressure be adjuster somehow without buying an adjustable fuel pressure regulator?


<< I don't think running lean is your problem. I had the EXACT SAME condition as you, and I fixed it with a new 2 core Modine radiator (there is no such thing as a three core Modine, contrary to info in this thread). >>

In the original post i listed all the cooling mods, i have run 2 radiators (stock 91 HD and now a GDI 3-core) no change at all. I have had the GDI pulled apart and cleaned like 3 times so far too.


<< what gearing are you running and what tire size, or is it all stock? >>

33x12.50 Superswamper SSR's on 15x10 Trailready Beadlocks.
D44 front, full float D60 rear, with 4.56 gears. 4 wheel disc and ARB's

The tires/gears/axles/brakes etc. where on before the overheating started i did however change the Wheels. they where some cheap lightweight aluminum 15x10's the trailreadys have steel centers.


<< also dont forget you can put on the heater and the temp goes down not too comfortable for the summer but it does stop the overheating >>

Actually I did run with the heater on in 100 deg temps on the freeway and it didn't help much i could go about 40 miles starting with a cold engine before it would boil over.

Last night i tryed setting the map adjuster to 6.0 volts and the check engine light came on; code 14 map sensor voltage. how high can you run it without it throwing a code?

I hope i don't sound like an ass answering all these questions so short. I really appreciate all the ideas and i know with everyones help we can get this XJ to run cool again. (well at least as cool as you can an XJ)

Did anyone catch the post on possible making a 02 sensor adjuster?

Thank you and keep the ideas coming.

Dingo

[Dingo509]

trans temp, well i installed the sending unit in the wrong spot its after the radiator but before the aux. cooler. it stays cool at first but after about 30 mins. it mimicks the engine temp with a delay its never gotten above 200 though.

Where is the best place to put the sending unit besides the pan. out going or return line?

Dingo

[CRASH]

trans temp, well i installed the sending unit in the wrong spot its after the radiator but before the aux. cooler. it stays cool at first but after about 30 mins. it mimicks the engine temp with a delay its never gotten above 200 though.

Where is the best place to put the sending unit besides the pan. out going or return line?

Dingo


Do you have the trans running through the OEM radiator fittings? If so, pull it out and just run it through the aux.

CRASH

[Gojeep]

You cannot build an adjustable O2 sensor. The reason is that is does not run a reference voltage like a Map does is it makes it's own voltage according to the conditions of the fuel mix. We are only talking around 1 volt.

[rsalemi]

you can increase fuel pressure by making your own adj regulator. Get a 1/4X20 long nut (sold to join 2 pieces of threaded rod together) and epoxy it over the vacumn tube - then cut a piece of 1/16 rod - I used welding rod -to fit under a 1/4X20 bolt. You need VERY little adjustment to raise the pressure - 1 flat raised mine 1 lb. - If you want to run the stock vacumn you also need to epoxy a vacumn port back on the reg. as you have blocked the original.

[Dingo509]

i like the idea of that adjustable regulator. looks like a trip to the hardware store is in order. What pressure should i run it at to start with?

Dingo

[Roll-over]

really dumb question... you said it overheats on the trail... going uphill or level terrain?

[Dingo509]

update
fuel pressure at about 50 Gauge bounces between 40 and 60 and map sensor at 6.00V Its running rich now, i can smell it and it hardly idles but guess what
NO CHANGE!!
Im hoping to make the NW run this year but as it stands i can't drive across town with our recond hi's almost 70

Anyway any other ideas?
Dingo

[CRASH]

update
fuel pressure at about 50 Gauge bounces between 40 and 60 and map sensor at 6.00V Its running rich now, i can smell it and it hardly idles but guess what
NO CHANGE!!
Im hoping to make the NW run this year but as it stands i can't drive across town with our recond hi's almost 70

Anyway any other ideas?
Dingo

Shocking.

In your specific case, you do not have nearly enough mods to be out of the OEM mapping parameters, so don't sweat it.

[C85D4x4]

i dont get whats going on with some of ur xjs?
i never have a heating problem in my 93
the temp gage never gos more than half way

maybe its b/c i live in ohio

[Dingo509]

Shocking.
I agree Crash but at this point im out of ideas, so what do you recomend? I'll try just about anything.

Dingo
Now enrolling in voodoo and witchcraft classes

[CRASH]

Before i get yelled at for this let me give you a history:

91 XJ 4dr. 233K 4.0 aw4 with a/c
In order of install per item
2 Radiators a stock 2 core and currently a gdi 3 core
3 water pumps 1 mopar, 1 cheap rebuilt, currently new aftermarket
6 thermostats mopar, 4 aftermarket 2@180, 2@ 195, currently mopar
2 heater valves, both mopar
2 t-stat housings both mopar, currently hand ported
all hoses have replaced at least twice

Fan setup went from stock electric and mechanical to dual electric (1 stock 1 flex-a-lite 110) to dual flex-a-lite 110

Other mods 99+ intake swap, 60mm throttle body, donaldson airbox rated at 350 cfm, 98 5.2L durango injectors

I have pulled the head and it checked and machined flat (.007 max is .006)
I can drive it just fine if the temperature is below 60 otherwise it overheats
Mainly on the freeway, i can sit idle in traffic at over 100 ambient and it runs below 200 all day. it also overheats very fast when pulling steep grades, at any speed or ambient temperature.

Ive been fighting this for 3 yrs. now and basically can't drive it in the summer.
Any ideas?

Dingo


Have you checked your cat? Is the power OK? Clogged cats can really heat up a motor.

Is there a spring in the lower radiator hose? IF there isn't one there, the hose can collapse from hydrostatic pressure under high fluid passage.

I hate to say it, but can you get your hands on a different radiator? Preferably a virgin one? Modine would be best,.....

[Ed A. Stevens]

Check the catalytic converter first. Drive it to heat it up to where you have the problem. Uncork the exhaust before the cat (if possible) and test drive it hot (noisy, but effective) and report back if the top end power and overheating goes away? A restricted cat will cause all the problems you report.

Is the new aftermarket water pump the correct (reverse) rotation?

Is the volume of water bypassing the radiator through the heater valve excessive (do you have a flow restrictor in the valve or heater core bypass hose)?

Is the air dam and shroud under the radiator support in place?

[Dingo509]

Have you checked your cat? Is the power OK? Clogged cats can really heat up a motor.

Is there a spring in the lower radiator hose? IF there isn't one there, the hose can collapse from hydrostatic pressure under high fluid passage.

I hate to say it, but can you get your hands on a different radiator? Preferably a virgin one? Modine would be best,.....

The cat's hogged out nothing but a resonator now.
The Lower hose is a new mopar one with the spring
I talked to radiator shop today where i got my gdi about swapping me for a modine since the gdi didn't fix anything since the begining, i have to talk the owner (Who's is very willing to help) mon.

[Dingo509]

Is the new aftermarket water pump the correct (reverse) rotation?

Is the volume of water bypassing the radiator through the heater valve excessive (do you have a flow restrictor in the valve or heater core bypass hose)?

Is the air dam and shroud under the radiator support in place?

The water pump is correct rotation i verified with a buddy's 95 since he had his water pump out at the same time. the new is an airtex btw.

I don't know if there is a restrictor in the heater circuit or not. all four hoses and the valve are new mopar parts.

The air dam and shroud under the radiator where removed probably 6 yrs ago. about 3 years before the problem started.

dingo

[Ed A. Stevens]

I don't know if there is a restrictor in the heater circuit or not. all four hoses and the valve are new mopar parts.
dingo

The heater valve may be full port (5/8 unrestricted flow) on both the heater circuit and the bypass circuit. If the bypass is full port the coolant diverted around the radiator will impact the cooling (but usually not as much as you report).

Are you still running the dual electric fans?

[Dingo509]

The heater valve may be full port (5/8 unrestricted flow) on both the heater circuit and the bypass circuit. If the bypass is full port the coolant diverted around the radiator will impact the cooling (but usually not as much as you report).

Are you still running the dual electric fans?

At the moment yes i am running the dual electrics. I am planning on putting the mech fan back on as soon as i find a stock shroud, lost the original.

I thought about trying to run the heater hoses directly to the heater core and then put a block off style valve in instead of the bypass. I think dodge FS vans around late 80's early 90's used a valve like this that was vacuum operated. The main thing i was worried about was the posibility of cavitaion at the water pumpfrom the lack of collant flow.

I also thought about using a large trans cooler as sort of an aux. radiator on the heater return line before it went back to the water pump. Whenever i get my OB shower done the heat exchanger will fit into the right fender and will run after the heater so that might help cool that part of the system plus add more coolant. Outside of exchanger is 3"dia x 24" long copper pipe. But that's a whole 'nother story.

Dingo
Ancient XJtribe cooling dance failed too
Starting voodoo next week

[Ed A. Stevens]

At the moment yes i am running the dual electrics. I am planning on putting the mech fan back on as soon as i find a stock shroud, lost the original.

Dingo
Ancient XJtribe cooling dance failed too
Starting voodoo next week


I expect the return to a mechanical drive primary cooling fan and shroud will solve the problem. The increased pressure under the vehicle, and behind the radiator, at speed is reducing the air pressure difference across the radiator core that promotes airflow. This is (one reason) why it works at idle and slow speeds, but overheats at highway speed.

Few have proven a reliable electric fan conversion to be successful. The power draw of some of the new fans (Taurus and Benz fans) can overcome the increase in pressure that builds under the XJ at speed but they are not small enough to fit. Few aftermarket fan blades and motors are designed to pull the 40+ amps that are needed to power the significant airflow and pressure drop required. They flow great with low amp draw with minimal external static pressure on the exhaust side of the blades, but quickly lose airflow if they encounter any pressure resistance.

Good Luck.

[Gojeep]

This does not make sense to me at all. There should not even be a need for a fan of any type at speed. There is another problem here some where. I first thought cavitation but that would happen at slow speed too with high revs. What does bother me is how much of the frontal area is blocked with lights or winch? Is the problem that the air is backing up due to extra battery or other gear added under the hood? Have you tried just spacing up the back of the hood an inch to see if this improves the airflow?

[rsalemi]

One other thought - leaking head gasket - Get a radiator shop to pressure test the system - a compression leak into the coolant holes will cause overheating.
And I second Ed's thoughts on the mechanical fan - I solved an overheating problem on my 4.0 by replacing the fan clutch with a HD one from Summit Racing - sounds like an airplane but cools the motor!!!

[Bradlybob]

I'm currently running a flex-a-lite 110 fan set up too and have had no resolution to the o'heating problem. I have tried everything except going back to the stock fan and using a Modine rad. By the way mine acts the same as yours, o'heats on flat freeway even. I was kind of wondering about the A/C condenser restricting airflow through the rad. It's clean on the surface, no bugs/mud, but I can barely see through it. The fins on the surface are straight but deeper inside core they seem to be kind of twisted, not like a rad where you can see straight through when viewed at the correct angle. I replaced the air dam and that didn't help either. I'm about ready to buy a YJ!

[Dingo509]

This does not make sense to me at all. There should not even be a need for a fan of any type at speed. There is another problem here some where. I first thought cavitation but that would happen at slow speed too with high revs. What does bother me is how much of the frontal area is blocked with lights or winch? Is the problem that the air is backing up due to extra battery or other gear added under the hood? Have you tried just spacing up the back of the hood an inch to see if this improves the airflow?

on the front i have a custom 4x4 front bumper w/grill guard warn xd9000i with soft cover and 3 hella 500's (i'd post a pic but i don't know how) BUT all this was on before the problem started. inside the battery is gone and there's a york in it's place. The only thing about blocking airflow is that id doesn't overheat just on the hiway, it also does it at 15 and up pulling a steep hill.

I have holes cut in the hood now will spacing the hood help more if you think it will i'll try it.

Dingo

[Dingo509]

One other thought - leaking head gasket - Get a radiator shop to pressure test the system - a compression leak into the coolant holes will cause overheating.
And I second Ed's thoughts on the mechanical fan - I solved an overheating problem on my 4.0 by replacing the fan clutch with a HD one from Summit Racing - sounds like an airplane but cools the motor!!!


Im going to swap back to the clutch fan as soon as i find a shroud. would you guys recommend the clutch or just a spacer?

I tried the head gasket, checked the block .001 warp, within spec. the head was .007 max twist is .006, had the head machined .008. No change.

Dingo

[Dingo509]

I'm currently running a flex-a-lite 110 fan set up too and have had no resolution to the o'heating problem. I have tried everything except going back to the stock fan and using a Modine rad. By the way mine acts the same as yours, o'heats on flat freeway even. I was kind of wondering about the A/C condenser restricting airflow through the rad. It's clean on the surface, no bugs/mud, but I can barely see through it. The fins on the surface are straight but deeper inside core they seem to be kind of twisted, not like a rad where you can see straight through when viewed at the correct angle. I replaced the air dam and that didn't help either. I'm about ready to buy a YJ!

What else have you tried? maybe between us we can t
fix theses things once and for all.

Dingo

[wsuxjer]

Brian, do you still have the stock block in there? Stock cam, etc?

[Dingo509]

Brian, do you still have the stock block in there? Stock cam, etc?

Yeah the internals are all stock, the intake and exhaust are all upgraded.

Did you ever work at Camp Fife?

Dingo

[CRASH]

This does not make sense to me at all. There should not even be a need for a fan of any type at speed. There is another problem here some where. I first thought cavitation but that would happen at slow speed too with high revs. What does bother me is how much of the frontal area is blocked with lights or winch? Is the problem that the air is backing up due to extra battery or other gear added under the hood? Have you tried just spacing up the back of the hood an inch to see if this improves the airflow?

To the contrary, if I unplug my electric aux. fan, I run 15 degrees warmer on the freeway. Fans perform a service at highway speeds as well as slow speed situations.

Dingo, get that mech. fan in there and report back.

CRASH

[FUNKYTEE5]

One other thought - leaking head gasket - Get a radiator shop to pressure test the system - a compression leak into the coolant holes will cause overheating.
And I second Ed's thoughts on the mechanical fan - I solved an overheating problem on my 4.0 by replacing the fan clutch with a HD one from Summit Racing - sounds like an airplane but cools the motor!!!

Ditto on the leaking head gasket. It sounds like the motor has gotten hot quite a few times? I just dealt with the notorious 2.5 liter Subaru head gasket problem. Only had symptoms after 20 miles or so, or pulling up a grade, then it'd boil over. You can have a shop do a hydrocarbon test in the coolant to rule out a leaking head gasket. I suspected everything but the head gasket on that one! It'd be best to get it done while symptoms are present. Many times these leaks will only open up after being warmed or under load. Also, have you tried running with the t-stat out? Does it still boil over? Good Luck:)

FUNKYTEE5

[wsuxjer]

Yeah the internals are all stock, the intake and exhaust are all upgraded.

Did you ever work at Camp Fife?

DingoYup. ;)

I would think the problem lies somewhere else other than your cooling system. Try putting the mechanical fan back in like Crash said, and check the head gasket and pressure test the cooling system like others said.

[Gojeep]

I will say it again, dont run the flexy-lite 110. They are shocking at cooling and will even lose fins later on!
Running three lights across the front it is not helping at all either. I have two electric fans and they have never come on at highway speeds no matter how hot it is including over 100 degrees while towing in the Outback. If your fans come on you have an inadequate radiator or water pump. Thats why there is more than a fan problem here as well.

[Dingo509]

I will say it again, dont run the flexy-lite 110. They are shocking at cooling and will even lose fins later on!
Running three lights across the front it is not helping at all either. I have two electric fans and they have never come on at highway speeds no matter how hot it is including over 100 degrees while towing in the Outback. If your fans come on you have an inadequate radiator or water pump. Thats why there is more than a fan problem here as well.

you're right about the damn fans losing blades i just lost blades on one again today so now i'm down to only one fan. As far as the lights i've taken the whole grill guard off and it didn't change anything. the fans are always on because i've rewired them to a switch in the overhead console.

So this is my next plan of attack
1. leave one fex-a-lite 110 in place of the stock electric (i will replace this later with a stock 95-up fan) and reinstall the original fan with a spacer.
2. Replace the temp sensor for the computer and the Air temp sensor
3.Replace the GDI radiator with an aluminum from alumrad.com this has 1 3/8 single tube.

If that doesn't work then i will put of the coilover project and by the $1000
Be Cool kit that includeds the radiator and fans.

Then If that doesn't work Buy a 97+ and spend the next year swapping parts.

If THAT doesn't work burn down everthing and buy a honda Or shoot myself in the head (same result in the end)

What do you think?
Dingo

[Bob Langford]

How about the thermal viscous fan drive ? I didn't see it mentioned as one of the things replaced in the first post on this thread. I could spin mine easily with the engine cut off, but there was some thick fluid oozing out of the clockspring-like mechanism on the front. So, I swapped it out. Made all the difference. My 96 XJ behaved exactly as you described above: ok when idling, but when under load, temp would climb. For a long time, I ran the aux fan anytime I saw the temp creep up (I wired to a switch inside the cab where I could apply 12v to it).

[hotrod76car]

I was woundering if you fixed your overheating prob yet. I had the same one and put the aluminum rad in and fixed mine

[Dingo509]

I was woundering if you fixed your overheating prob yet. I had the same one and put the aluminum rad in and fixed mine

as of right now, the XJ sits apart in the driveway for more upgrades/repairs. 4 link longarm setup, new trackbar, onboard shower, and fix the rear ARB.

I just ordered the Visteon aluminum core radiator from radiatorworld.com for $116. this is the same (by spec) radiator as the have listed on Alumrad.com
i have also ordered the 14" Zirgo electric fan, as the mechanical fan does not fit well with the york compressor. I have also relocated the transcooler lines so they don't go thru the radiator anymore. I will post an update when i get this thing back on the road.

Dingo

[Dingo509]

okay final plan of attack included a new Visteon aluminum core radiator with a single 1 3/8" tube, a 14" zirgo fan, the stock 93+ electric, bypassing the trans cooler in the rad, and removed the AC condensor. While i had the fenders off i installed the heat exchanger for the onboard shower, the coolant circulates through this full time and it added about a gallon to the cooling system. look for a write up soon.

The XJ never got over 210 the whole weekend of the NW fest. In town, stop and go it was well below 190, on the freeway it approached 210 very quickly but did not go over, and the major problem i WAS having was pulling hills. the entire 30 min climb to the trailhead it never got over 210. This leads me to believe the whole problem was initially caused by the GDI 3-core creating a restriction in the system.

As far as having to remove the fan pulley to install a zirgo electric fan, not so. IF you want to move the top of the radiator forward about an inch. I will have pics up soon on this too.

Thank you to all involved in helping me diagnois and fix this problem that has been annoying me for over 3 years. This is the reason NAXJA is the best.

Dingo

[krakhedd]

delete this post please admin

[Dingo509]

delete this post please admin

Can i ask why you think this needs to be deleted?

Dingo