Anthonyb

Ok, my 96 sport is getting warm when I go up hills, or am stuck in stop and go traffic(215-220). The water pump was replaced a couple of months ago. It leaks or burns 0 antifreeze, I marked my own hot and cold levels with a sharpee on the overflow bottle, and they are consistent. Once I get back on level roadways or up to a constant speed the temp eventually goes back down to normal levels, however, if I drive for an extended period(45 miles or more) on hot days it creeps up to around 220-225 and holds.

Any thoughts or ideas? Should I replace the thermostat? Flush the system? Also when is the auxilary E-fan supposed to come on? Mine seems to not be coming on. Is that not coming on enough to cause this overheating? Keep in mind it never gets to full-on overheating temps just hits 220-225 and holds... Thanks.

TrailLover93

Could be a clogged water jacket that makes it not properly cool the engine when going up hills?
Also, what is your oil pressure when driving up the hills?
Is there any sludge in your coolant overflow, and did you notice any when the waterpump was done?
You can wire your aux fan into your ignition block so that it will come on when the car does. Just one idea..I had to do that years ago on a grandprix I had.

Anthonyb

Oil pressure is pretty consistent at 55-60 when going up the hill. It's on my way to work so the Jeep hasn't been run more than 10 minutes or so and hasn't warmed up totally yet to the point that the pressure goes down. It'll run at 55-60 for about a half an hour before it will settle to 45ish and my drive to work is 25 minutes. There is no sludge in the reservoir, and when the pump was done my mechanic never said anything, and he would have he's a very trustworthy local mechanic who does a lot of stuff for me that I can't do.

Coolant is still bright green and shows no signs of burning.

TrailLover93

I dunno then. Sorry I couldn't be anymore help. I hope someone else can shed some light on the situation. I have a general knowledge of vehicles, mainly yota's, but I am just learning about jeeps in detail.

az4wheeler

make sure there is no air in coolant system, 4.0's are famous for them the air likes to get trapped in the heater core, raise front of vehicle up and when cool take rad. cap off and start it as it warms up if there is air it will burp through the rad. cap opening just add coolant as needed. may take 15 to 20 min.

jth877

This ^^^^^

Also, you could replace the rad cap. If it's old, it might have a slight leak especially if you changed the rad. Did you replace the thermostat? Super stants seem to be more consistent and flow a little better. Reverse flush the heater core/rad. Make sure all the air is out. Some people drill a 1/8" hole at the 12 o'clock position on the thermostat flange to help in burping.

Anthonyb

Cool thanks guys, I'll give some of that a try on Sat. when I have time. I am going to change the thermostat, and I did try to burp it once, but I didn't spend 15-20 minutes doing it. If the radiator cap is leaking would the fluid loss be noticeable? I haven't had to add fluid since april when I changed the WP, and it has been consistently the same level...

DrewsBrew

I have an overheating problem as well.
1998 XJ with 4.0L (230,000 miles on original, 60 miles on new motor)and AW4, Open cooling system (Not the older closed system design)
It started last summer at highway speed with A/C on.
It would not overheat in the morning when the ambient tempurature was under 90 but it would overheat during the afternoon commute with ambient air tempuratures above 90 degrees. (Dallas, Texas)
It would creep up and over 210 then do the check gauge spike to just under 260.
When I turned the A/C off or slowed down at a stoplight the temp would come back down to 215.
I replaced the Thermostat 3 times with several different brands and with different temps 195, 180, 160, and back to stock 195.
I replaced the tempurature sender.
Radiator Cap.
I replaced the mechanical fan clutch.
I replaced the Electric fan and confirmed it is working properly.
I replaced the radiator twice, the first time with an aluminum unit and then six months ago with a GCI 3 core.
No blockage in front of Condenser/Radiator.
I replaced the water pump and hoses (Autozone parts).
I will replace the water pump again this weekend with a FlowKooler and with stock OEM hoses with the factory spring in the lower hose.
I figured I had a bad head gasket so I replaced the motor this last week with an ATK. (It purrs like a kitten)

Today I drove it to work (40 miles) and the temp did not spike right away but its staying above the 210. The last part I replaced was the electric fan (did not turn very fast) with a new one (spins super fast) and that helps a lot but I want it to stay at or below 210 and I am willing to spend any amount to keep this bastard from beating me down. I would like some input from someone with experience with this. I have decided that it must be a water flow problem since it overheats at highway speed which should negate the fan/air flow as a potential problem. The only thing I can think of at this point is that the autozone water pump from last summer is not a CCW unit or the lower radiator hose is collapsing under load. When I put the new factory hoses and FlowKooler on this next weekend, everything has been replaced including a new motor. Any suggestions. (I will update after I install the Flowkooler and OEM hoses)

96cherokeeswanga

Check the clutch fan if it has no tension when the motor is off then that might be the problem.just replaced mine.