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running out of ideas with this heat

scorpio_vette

NAXJA Forum User
yeah.....usually i'm the one helping people with their overheating problems, but i just can't figure this one out to save my life. i'm having both engine and tranny temp problems.

quick overview. yes i use my jeep very hard. on-road and off-road alike. i also take care of it even better as far as mechanical goes.

it's a 95XJ, 4.0L, AW4, 3.55 and 33's (now hold on, we'll get to that. just let me finish).


now obviously 3.55 and 33's isn't a very ideal combo. but it was sorta out of necessity. need tires, no money and got a set of 33's for free. so i could understand if that were to make the tranny run a little hotter, which if it was going through the rad, could/would make the engine get a little hotter.

BUT......this is my current setup.

3month old coolant flush,
few month old thermostat (opens and closes properly),
amsoil 5W-30
18,000# GVWR tranny cooler (completely bypassed radiator to seperate the 2 heat sources. spaced 1.5" in front of the radiator in front of the mechanical fan to ensure constant steady airflow)
brand new tranny lines
brand new all metal 2 core radiator not even 2 months old (not dirty at all. no mud)
brand new fan clutch (found mine to be bad)
brand new radiator hoses
brand new factory radiator cap (and in agreement with radiator recommended pressure)
dual tranny temp gauges (hot and cold)
no A/C (removed a/c to use compressor for OBA)

now my tranny cooler seems to be doing it's job to an extend. at any given time there is about a 30-70 degree difference before and after the tranny cooler with an average of 40ish degree difference. but my tranny still runs about 210-240 when coming off the highway or driving in the city.

and my engine temp is happy when on the freeway, but will occasionally go about 1 needle width past 210 (it used to sit PERFECT just a hair under 210 and never move). and when i get off the freeway or in city driving, it is starting to sit around closer to 215-225 (my aux fan comes on quite regularly).


what am i overlooking??? i basically have a brand new cooling system and tranny cooling system. i'm running out of ideas.
 
It is summer.
Running the stock gears w/33s is as though you were towing a trailer everywhere.
Adding extra temp guages probably makes you more sensitive to the temps than otherwise.
Aux fan works and cools things down, right?
You could also wire in a switch to run the aux fan full time, if you are concerned, however,
things sound normal to me... has the Jeep overheated or do the guages just make you nervous?
Also, have you considered that running the cooler through the radiator and then the tranny cooler will also help your tranny warm up in the winter?
 
Agreed with the above post - doesn't sound bad or wrong.

You've done a lot, what's left........high performance water pump, somehow checking for clogged coolant ports in the engine, making sure there is no trapped air in the system?

My temp is the same as yours and when it hits ~220 the fan comes on and cools everything down just fine. So far I'm not concerned - if my electric fan had to run near constantly then I'd be a bit concerned.
 
i'm not worried about the winter temps. all my lines are quick disconnect, so i can switch it back over to the radiator in a matter of minutes. i did it specifically for that reason. more cooling during the summer and a little warmer during the winter.

yes....i suppose to a small extend the gauges make me a bit nervous. i realize my tranny/gear/tire combo is bad, which is why i am trying to temporarily "bandaid" it with way oversize tranny coolers. as soon as i can get my hands on a set of 31's, or get some gears, that's getting handled. i'm by no means trying to make this an "acceptable combo" if you know what i mean.

but as far as the engine temps, i've never had the temp move over 210 even in summer. so while i can see the added stress of the tires, i didn't think it would affect the engine as bad as the tranny. but then again i guess it is in the same boat as the tranny after all.

oh and yes the aux fan works fine. it's also "newer" and i've checked it. i also replaced the mechanical fan shroud with a brand new one beginning of the year because my old one had a large chunk missing.

man i can't wait to get my rear 44 done and get a little extra to do my re-gear. i'm planning (hopefully it'll actually work out) to have it re-geared before the first snowfall.

anybody got a used set of D30/D44 4.88 gears???
 
Do you have a cracked ehaust manifold?

I have been tracking a simular overheating issue... Rock solid on the freeway at 210... Even in 90+ degree heat. Over heats while running in the sand dunes while at higher RPM. Quickly returned to normal while not running at higher RPMs. I am also running 3.55/aw4 with 31's

I have also noticed that it is like a needle widths hotter this summer than I think it should be.

Coolant flush in the last 12 months, new water pump, (12 months old) Aux fan runs good ....blah blah blah.

I found a large crack in the exhaust manifold that was blowing very HOT exhaust right back on to the side of the block. The crack is on the back side of the manifold. hard to see unless you stick your hand in there then you can feel the hot puffs as each cylinder goes through the exhuast stroke.

My new header arrived yesterday so I have not proved that the exhaust manifold crack is causing the over heating but I think it is a significant factor.

It is easy to check.. cost nothing to check out. Can be done in a few minutes.
 
yeah my manifold has a very fine crack. on the front side facing the fender just like 99.999% of every factory 4.0L manifold. it's actually been like that since i bought it, and just haven't bothered putting headers on yet. so i've kinda ruled that out since i didn't have heat issues before. only this year. i've even been wondering if maybe for some reason i might be running lean and that could/would increase the temps. but from what i've checked so far, it doesn't seem to be.
 
Try the Crown Automotive fan clutch for the 87-93 XJ part number#52003205. Its a heavy duty clutch and locks up much earlier than the stock 94 and later and works very well in moving more air to cool things down. I got mine through Rusty's. Hayden also makes a heavy duty clutch, part #2737 that will fit the cherokee, most auto parts stores do not list the Hayden heavy duty one, only the factory replacement. Hayden's web site has really good info on different types of fan clutches.
 
cap is 16psi, and i'm fine with the 2 core. if i'm going to start spending more money on "bandaging" the problem, then i might as well get smaller tires or better gears. both of which i don't have money for right now. LOL

i'll have to look into that fan clutch though. i've been wanting one that locks up sooner, but didn't have time to try and find one. i'm actually almost tempted to remove the clutch and replace it with a spacer. the noise wouldn't bother me, and it's already slow as it is, so a little extra drag wouldn't really matter anymore.
 
Torque converter not locking up? In my 95 crusing down the highway if you lightly hit the brake pedal you could easily feel the converter unlock. This in itself will make lots of heat. Im no expert on auto trannies but Ive never run those trans temps in any auto in my trucks towing a stock trailer and camper unless crawling up a hill with 0 air flow on the coolers. Just a thought.
 
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yeah i'll have to look into that. that's one thing that i'll admit straight up. i don't know shit about auto trannies. the only good thing about auto trannies is not having the 3rd pedal when in the rocks. other than that, i never did understand them, and there is to much shit to go wrong with them. to many un-necessary parts. i'll take a manual any day. i really wish i could afford to put a manual in here.

either way......i need to learn to understand these stupid things anyways.
 
Im not sure how much the TPS would have on throttle position/ lockup. Dunno AW4`s are definately one of the better autos and I sure wouldent trade for AX15 or NV3500 after the last Dodge truck with a NV4500.
 
I don't see your tire and gear combo making things hot. I ran that way for awhile, even after my stroker motor I had zero cooling problems with the motor. I don't run a trans guage but my factory cooler(tiny thing) is never all that hot(feeling it through the grill).

You being slightly above 210 is totally normal. IIRC the electric fan doesn't come on until 220 anyways(unless AC is on). Even on the trail with the AC on and 100* outside its never over 220 or so.

Sounds like you have a bad head gasket or cracked head possibly. Is your torque converter locking up when it should? That could effect trans temp.
 
scorpio_vette said:
...i really wish i could afford to put a manual in here.

either way......

I don't recall if the 95 had the ECU and TCU integrated together. If not, you're lucky......My 89 has 2 seperate units. If you unplug the TCU...Presto!! Instant 3 speed manual.
 
coolant temp sensor is oem, but i do want to get another one to see if the sensor might be off. like i said, the temps NEVER went this high until this year.
the tranny temp gauges are obviously aftermarket. i got them from my local mom and pop hot rod shop. they into everything from street rods, to race cars, from show cars to classics. they carry good quality stuff.


while the AW4 might have the reputation of being a good tranny, i'm not very impressed with it. i manged to blow one up on 31's. i'd trade it for an AX15, NV3550 or whatever that new TJ 6speed manual is, any day. my wife has a AX15 in her TJ, and i've been swearing for the last 4 years that it's dying. but it never does. that tranny has gone through hell and back and just keeps working.

head gasket is fine. i just took the motor apart about a year ago and replaced every gasket in it. the motor looked very clean, and currently has no leaks internal or external.

i'll have to look into the torque converter possibility when i get some time from work. been crazy busy lately.
 
scorpio_vette said:
yeah i'll have to look into that. that's one thing that i'll admit straight up. i don't know shit about auto trannies. the only good thing about auto trannies is not having the 3rd pedal when in the rocks. other than that, i never did understand them, and there is to much shit to go wrong with them. to many un-necessary parts. i'll take a manual any day. i really wish i could afford to put a manual in here.

either way......i need to learn to understand these stupid things anyways.

Grass isn't always greener on the other side....I've been thinking of switching to an auto:doh:
 
outlander said:
Grass isn't always greener on the other side....I've been thinking of switching to an auto:doh:

yeah but i have side by side comparison. my jeep is auto, and my wifes is manual. i try to drive my wifes jeep as much as i can. but she generally doesn't let me drive it unless it needs to be fixed.
 
When I first bought my 88XJ(used), it had a random overheating problem. Since it was under warranty, I took it back to the dealer and they pressure tested it and found nothing wrong. I kept looking out my rear window for a puff of white steam, but nothing. Then on a hot day, I saw a puff of white steam for an instant. Apparently, when it got really hot the head would lift slightly to release steam into the combustion chamber and out the exhaust. There was never any water in the oil. Anyway, I took it back to the dealer and they pulled the head, resurfaced it, installed a new head gasket, and the problem went away.

Hope this helps.

Best regards,

CJR
 
someone mentioned rewiring your Aux fan to be on all the time. I did this and makes my engine stay at around 185-195 while driving with a constant flow of air. runs at around 200 at a light on a hot summer day, then cools back down after i get going down the road. BUT..... While on the trail, even in the shade, the 2 fans working at the same time is not much help as its just blowing around more hot air and reaches temps of 220. I have also redone EVERYTHING you have mentioned you've done and yet i dont overheat while driving, its kept me from the trails for about a month untill it gets cooler.
 
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