Kosta0933

Hello everyone. I have a new to me 98 Cherokee with the 4.0 and AW4 transmission. It is lifted a bit and has 33” tires and has been re-geared all by previous owner.

since I’ve purchased, I’ve changed the radiator to a 2 row CSF, water pump, thermostat (mopar 195) thermostat housing (mopar) temp sensor (mopar), upper and lower radiator hoses, new mopar rad cap, installed the Napa ZJ fan clutch, new aux elec fan, and all with fresh coolant and I’m almost certain I burped it correctly. Everything turns on and works as it should, i would hope so that is.

** has transmission cooler and PS cooler installed by previous owner along with digital coolant temp gauge and transmission temp gauge. Previous owner never had issues with heat. Also heater core is not good, hoses are bypassed.

- Today is 90° in my part of California, and I thought I had my cooling system good to go. With AC on and after driving a bit around town, temp gets upwards to 235°. Trans temp according to the aftermarket digital gauge went up to 200°. Without having AC on, temp stays around 210, goes to about 214, elec fan kicks on then goes back to about 208 and stays for a bit too. Only with the AC on when it’s pretty warm outside I worry.

im not sure what else to check. There isn’t any leaks I’ve checked a few times.. is there anything else they can be affecting it. I also have hood louvers

note: this is my first jeep

awg

two things;

1) check the electric fan comes on when A/C kicks in, there is various faults will prevent this

2) Park vehicle nose steeply up, remove radiator cap, strat engine and fill neck to brim with coolant.

There should be NO, (or very few) bubbles. Let engine idle with cap off until thermostat opens, add any more coolant
Bubbles in coolant indicate a blown head gasket (will cause overheat)

It would be ideal if the heater was working, as this is another good test if overheating, turn on heater full blast max fan.

This acts like another radiator, and if it works, is indicative your radiator is inefficient

Very Red XJ

I don't know the free area of your louvers, but Spacer blocks between the hinges and the hood are cheap and will let more hot air out of the engine bay giving your fan a place to move the air on hot days. This old 6's produce a lot of heat

https://speedzone-web.com/products/n...4aAuMHEALw_wcB

Kosta0933

electric fan automatically kicks on when AC is on.

i will check the coolant again with the nose parked up. From what I remember I didn’t see any bubbles like it had rabies. Just the standard burping bubbles until it went away. But I will double check tonight

when it gets cooler I’m going to try to change the heater core myself. Also apologies but I got a little confused when you said if the heater core works then my radiator is inefficient?

awg

By turning on the heater with max fan, you are effectively expanding the volume of your radiator.

The heater is just a core, and the fan pushes air through it, so counter-intuitively, if you are over heating, do that.

If your radiator is "inefficient" (for any reason). this extra capacity will prove it out, to some extent

If your water pump impellors are worn, this test would make no difference

I hope this clarifies the issue in your mind

imo, the XJ has a somewhat marginal radiator capacity in hot weather (like mine)

I have new stock radiator, water pump, and larger trans cooler, rest is stock as it came to me, it behaves, in that it has not overheated in my 7 years of ownership (but they want to under extreme conditions, my last one did)

Kosta0933

ah ok I understand now about the heater core.

Update* last night I had the rad cap open and let it run in idle for close to 45 min. Letting the elec fan cycle on and off on its own. Didn’t creep up. Also coolant isn’t foaming with bubbles, coolant stayed in the radiator wasn’t blowing out, oil isn’t chocolate milk, and no smoke from tail pipe. I will test to see if there is combustion going in the coolant (I hope there isn’t) to put my mind at ease if it isn’t. if it passes I have other theories maybe you guys can shed some light on.

1. when trans temp goes to about 200, I notice that’s when coolant temp creeps up with AC on, aftermarket transmission cooler is in front of condenser (so it’s grill, cooler, condenser, then radiator) the cooler is only about a 7”x7” cooler. Fan sucks in air, I used the paper method, I put a paper on the grill and the paper stayed, not really official test I guess.

2. When AC is on, AC clutch always spins, I always thought it was intermittent where it spins, stops and spins again? Clutch doesn’t move when AC is off. Could it be going out and drawing more causing it to heat up a bit?

3. potential head gasket failure? I hope not. I know how to work on cars but not that great.


the fan clutch is new I installed it, it’s the Napa 272310 and has fan shroud as well. Previous owner mentioned he always had a hard time burping the system when he would change the coolant, he’s owned it over 10 years. So not sure if still air in system?

thermostat is new mopar 195° with jiggle valve. It came in a 2 pack from a mopar Amazon store. Not sure if it’s a bad batch or?? Point is, I just want to drive it in all seasons without overheating worries.

bweb

When it's running and all warmed up did you check to make sure the radiator hoses aren't collapsed? Don't know if Jeep has them but some vehicles have a spring in the hose to keep them from collapsing.

Kosta0933

hoses are new and I did check. No collapse. The upper hose is Napa. Lower is a new mopar one with spring in it.

Very Red XJ

I live in California and like any reasonable person, I go to the mountains when it's hot. However, I often have to cross a low desert valley before I climb. My stock cooling system over-heated in the valley. So, I exchanged my radiator for a thicker two-row high capacity Mishimoto radiator and vented the hood to let the hot air out: in addition, a slightly larger transmission cooler comes with the deal. No cooling problems for 3 years. However, when I went across a different valley this August @ 100 degrees and started climbing in 4-low, with the AC on - the temp gage started to climb. I turned the AC off, rolled down the windows and watched the gauge drop. Soon, we climbed to a cooler elevation. I considered a three-fan accessory - but if this is as bad as it's been with the stock the two fan system: https://www.mishimoto.com/jeep-cherokee-xj-aluminum-radiator-1989-2001.html

bluejeep2001

You talk about 200 deg tranny temp....from any chart i have seen, that's dangerous and damaging. You say you have an external tranny cooler. Per JEEP, thats supposed to be plumbed in after the fluid goes through the tranny cooler in the radiator...not a stand alone cooler. My external tranny cooler is directly in front of the mechanical fan so it always has cooling air over it. Any other position is dependent upon jeep speed or aux fan condition.

00t444e

Get rid of that radiator and put a factory replacement in.

Kosta0933

I have a new Napa radiator that I didn’t install, it’s a OE replacement, I decided to use the csf two core.

but it was still doing this with the original Radiator in after I replaced the other cooling parts.

with ac on, ac clutch keeps spinning, I always through they were intermittent? Could this cause coolant temp creep? Or bad t stat even though it’s new mopar but I bought it from an mopar store off Amazon. Or radiator is junk?

I still want to test if I have exhaust in the coolant

Very Red XJ

The AW4 runs a little hot retaliative to other automatics, but like all automatics it runs best on warm fluid. This is why the trans cooler is located in the radiator - the engine heats the coolant which ,intern,warms the trans fluid. However, things go VERY bad between 220 - 235 degrees. 190 degrees is not an unusual temperature for an AW4.. Blue Jeep is correct - run the fluid through the trans cooler then through the optional cooler.

Very Red XJ

BTW, your 2 row CSF radiator is 1.26" thick made from copper & Brass. "Factory replacements" are usually a factory in China. Chrysler Factory replacement parts were all sold to a vender who quickly sold out of all popular items. My Mishimoto Aluminum radiator is 2" thick with no plastic parts. Aluminum transfers heat faster than copper or brass and the thicker cooling Finns have more surface to transfer heat.

Kosta0933

is the radiator plug and play? Also since it’s thicker, will the Napa 272310 fan clutch fit good?

if I don’t have combustion in the coolant and all is good I’ll get the radiator you sent