hudfabxj, I know you mean well.

But I speak from direct, expensive, hands on experience. My post above is every bit as likely as your theories. Maybe more so based on what the OP is telling us. Mine was doing the exact same thing his is.

No amount of diagnosis, expert opinions, etc. solved my problem. The problem existed before and after a complete professional rebuild.

Going back into a freshly rebuilt engine and replacing the freshly rebuilt head did fix it though.

 

Both of u folks need to keep all of us posted on your results of restricted coolant flow.

Here are 2 articles saying "slowing coolant down is the wrong way to go"

http://www.arrowheadradiator.com/14_...utomobiles.htm

http://www.stewartcomponents.com/tec...ech_Tips_3.htm

Again, that "how to radiator restrictor" write-up plainly stated the results were "at 75F ambient" and all I'm saying is just about any cooling system, even restricted, will perform well/keep the motor cool in 75F ambient.

Both of u fellas have replaced your cooling systems and are still overheating.......we're all trying to figure out why.

Please keep us posted with the restrictor results.

 

Interesting articles. I still think I will try it what do I have to loose.

 

U have nothing to lose, it's called modding, tinkering, southern engineering, whatever.......just report back with your findings.

 

Hudfab is the op. And no matter what if there is no.exhaust gasses in the cooling system, there is no crack have you read this whole thread? Or just popped in mid way through?

 

Subed...

 

Well, it looks like you just popped in late.

I never said anything about exhaust gasses in the coolant. If you would have read my post, you would have noticed that I said the head is probably cracked internally. Not into the exhaust side.

 

Both of those articles state that a restrictor will decrease cooling efficiency. In my case, they increased it. Real world results are proving this to me.

Without the restrictor, it overheats. With the restrictor, still hasnt overheated. Seems to be the opposite.

Like I stated in one of my posts, I did not solve my problem. I just figured out how to make it not overheat.


Its been above 90* here in Colorado for some time. The base of I-70 is right outside my shop. There is no better test hill for a cherokees cooling system. I would overheat by the first or second exit going up the mountain before the restrictor. With the restrictor, I made it all the way past Evergreen with my temp right under 220*. If it didnt overheat by then, its not going to. Drove to Lyons Sunday, and loaded the jeep full of my fab equip yesterday to move shops. With over 1500lbs in the back(springs sagged a good 3 inches).....no overheating.

Going wheeling this weekend and will post up my results once again.

 

Glad it worked for u.......keep us posted.

 

I just read through the thread and I too don't understand why the restrictor would work but if it solves the problem then I reckon you can't argue with sucess can you? One thing though. hudfabxj says his temp ran just under 220* on his jaunt in Colo. I recently refurbed my 96's cooling system (ZJ fan clutch,OEM 195 stat,flushed engine/rad/heater core separately,power washed and compressed air cleaned both rad and AC cooler fins,oem rad cap,50-50 Preston and distilled water). I now run a max temp of just off of the right of the 210 mark under conditions that was causing my original high temp (just at the red) problem. Pulling a 5mi mountain with almost a constant 9% grade with AC on and a load of passangers. Air temp was actually higher than it had ever been before (mid to upper 90's). Most of the time it's running 195* to well under the 210 mark. And that's around town at low speeds with AC. What I'm getting at is that although his XJ isn't overheating,220 is still seems too hot especially after everything else he's done to the system.

 

What we need is some more folks to install the restrictor as shown in the "how to" link and post back with their test results....and test in 90F+ ambient temps with nothing but the restrictor being changed/added. 75F ambient won't test/prove anything.

Can't say one thing works when several things changed.......kinda like in that "how to" link, the fella goes thru what he did and at the end of the article he says something like "oh by the way, I also changed to a Stant SuperStat #XXX and it gave me the most perfectly stable temps I've ever had". Doesn't sound like a very "controlled" test of a restrictor to me.....to many apple/oranges mixed in.

 

"What we need is some more folks to install the restrictor as shown in the "how to" link and post back with their test results....and test in 90F+ ambient temps with nothing but the restrictor being changed/added."

I think I'll sit this one out.

 

Me to........but I am curious.

 

I'm a bit curious about this. Not sure I want to give it a shot yet. Just swapped an engine from a 98 into my 92 and I'm having some overheating issues. Entire cooling system is new, flushed and burped it numerous times. I'm running a 180* thermostat with two 1/8" holes drilled in it, a high flow water pump OE replacement radiator. My winch blocks a bit of my radiator and I have an aftermarket transmission cooler. I'm going to try switching to a 195* thermostat, replacing my new fan clutch with a new ZJ v8 fan clutch, and I'm going to try relocating my transmission cooler.

I pulled the water pump and fan clutch off my old engine as I just replaced them about a month ago, radiator was also installed prior to the engine swap, didn't have any overheating issues with the old engine so I'm kind of at a loss.

If all else fails I might give this a shot.

 

Ok I didn't go to the extreme like hudfab but here is what I did. I took an extra hose clamp and tightened it on the upper hose as much as I could to restrict the flow. I did this in case there were issues on the way to work I could just remove the clamp. I am sure it isn't as restricted as hudfabs or the one in the link I guess I was hoping for some improvement.



It didn't work as I had hoped. It heated up quicker but didn't quite go as high as it has in the past. It is 92* outside and this was just a quick 2 mile run up a local hill. I would hate to see how hot it would get on a long mountain pass.



Hudfab thanks for posting the link and I am glad it worked for you. I guess I just need to start looking at more than just the cooling system.