As am I. Believe me, I was not looking forward to it. I really need to find out this overheating issue though, can anybody help?

 

Replace the coolant overflow bottle and the cap. If the cap cant hold pressure your system will not work thus leading to overheating.

 

Duct taped the bottle, cap hole (Without the cap on), and overflow valve thing. Still had the same problem, so I don't think It's the cap or bottle. Thanks for the suggestion though, they are all very welcome here.

 

Here is exactly what the Jeep is doing from what I can see:


Parked: Start it up, it gradually gets up to running temp with no pressure in the top hose. Once it gets up to running temp, the thermostat opens and the top hose becomes pressurized. From then on, the top hose slowly loses pressure until there is none left. Jeep begins overheating. This is about a 20-30 minute process.

Driving (Calm city driving): Jeep gradually gets up to temp. Once its up to temp, it stays there like it should while driving, but when I let off the gas the temp rises. If I sit at a light or stop sign the Jeep will overheat, but as soon as I start driving it the temp drops back down to normal in a reasonable time. Driving home I have a problem with overheating; I live on the top of a mountain and it's all uphill to get home.

 

Have you checked your clutch fan I upgraded mine today after having it blowing coolant everywhere when I least wanted it too. I was on one of the other sites and see a post about switching to a 97-98 Grand Cherokee clutch fan from napa p/n 272310 that increases air flow quite a bit. After I put it in it didn't even get up to 210 after letting it idle for a hour, BIG difference. I think my old clutch fan was bad so I figured I would upgrade since I was changing it.

P.S. The new clutch fan was alot bigger but it fit in with no modifications.

 

I have not checked that yet but I will try and remember tomorrow before I start it up. If the clutch is bad, I will just yank the mechanical and throw in an electric fan as I plan to do so soon anyway. I just need to compose a list of compatable fans and hit the yard for one. To tell you the truth, I kind of hope it is the clutch now that I've thought about it.

 

I am having the same problem as you,,,replaced every damn thing shy of the head gasket which I just purchased from Auto Value for $40 dollars canadian($30 for normal one but,I paid the extra $10 for the severe Duty Felpro one)the other day and my bro says its about a 4-5 hour fix!!Plus I am having the head pressure tested and planned which will set me back $150 but its well worth the peice of mind.Will let you know how I make out!If this don't fix it I am swapping it out for another 4.0l(HO) I have in my parts jeeps,,,but instead of going through the trouble of engine swap I'm gonna try this route first!

 

Good luck! Looking forward to hearing the outcome of this.

 

Well I've run that oversize clutch fan in the jeep for two days now driving it like I stole it and it hasn't overheated any. Actually it was all I could do to get it to stay at 210 degrees.

 

Congrats! If I wasn't looking to delete my clutch fan and install another electric unit I would definitely take that into consideration.

 

I've got a theory for my whole overheating problem. My theory is that the transmission is overheating and is causing the engine to overheat because the factory tranny cooler is heating up the coolant in the radiator. The symptoms I'm having all seem to point towards this. If I stop at a stop light after the jeep is warmed up the temp guage starts to rise... if I pop it into neutral or park the temp stays stable. I'm looking into a B&M trans cooler now.

 

Does your fan turn on while you are idling?

I was having the same problem before, dumping fluid, overheating, replaced a bunch of hoses, thermostat, and water pump. Turned out my electric fan was fried.

I could drive above 45mph or so, as the wind would cool it down. But as soon as I started to slow down, it was all over.

 

Electric fan works just fine. (Besides that one time when I forgot to connect it... oops )

 

So, my problem has been diagnosed. My Jeep has been overheating due to an overheating transmission from running 33's on 3.55's. I have a 14,400BTU B&M trans cooler and B&M Trans temp guage waiting to be installed.