Alright: 89 YJ with a Chevy 350 (GenI), Mepco 4 core automatic radiator, TH350 with a 24K GVW tranny cooler, Redline water wetter, 30% antifreeze, 185 degree thermostat and hi flow water pump.

Fawker will run at 230 degrees no matter what you're doing. Doesn't matter what thermostat or radiator I run.

Any ideas?

Well it could be a couple things.
Do you have anything blocking the grill? Jeeps do not flow much air as it is and putting shit in front of the grill does not help. Also, what kind of fan are you running. If it is a mechanical fan make sure you are using a shroud that works. Fan shrouds increase the efficiency of a fan by around 50%. If it is a electric fan it probably is not big enough for that size engine. There are few that are for a small block in a Jeep. Flexalite Black Magic fan is about the only one. What are the measurements of your radiator? The rule of thumb is you need the same surface area in the first row of the radiator as the displacement of the engine. In other words you need a radiator with 350in sqrd front surface. That can be tough to do. I see you are running a 4 core radiator. You might want to step back to a 3 core. 4 Core radiators are horribly inefficient. Many 3 cores cool better, because the cores in front of the others heat up the air passing over the cores behind them. Also aluminum is more efficient at exchanging heat than the standard brass and copper style.


A few ideas at least

Ben

Sorry, forgot to mention.

Got a Warn X9000i in front.

Electric pusher fan (2900CFM), flex-a-lite mechanical puller (3100 cfm). No shroud yet. Not susre of radiator size. mepco says it keeps their jeeps cool in Utah in the heat. Moab tested.

Grendel,

Sounds totally like an airflow issue, I 350 should be a piece of cake to cool, I mangaged to get my SB 415 under control in my CJ-7.

To do this I got a dual SPAL fan set up. SPAL Fans (http://www.carolinarodshop.com/11dual.htm)

If that won't fit on your radiator, go to a Flex a lite Black magic fan, that single bladed booger will move 2700 CFM+, it helps to build a shroud for you electric fan also so I pulls thru the entire core rather than just the center.

If that does not do it, go to www.daymotorsports.com and order a Griffin Aluminium 27.5x 19" racing radiator, pull out the ole sheetmetal shears and trim the grill out to fit this bigger radiator.

I run the griffin and the Dual 11" SPAL fans and my engine will hold 170 most of the time.

Hope this helps..

i would try this:

remove the electric fan altogether
remove the aftermarket fan
get a shroud
find a factory fan with alot of blades and put it on
test drive


i used to race circle track and could not keep the engine cool with an aftermarket 17" flex-fan. someone told me to go to the junkyard and get a shroud and rigid fan. the problems went away immediately. i would bet the electric is blocking more air than its letting go thru.

do you have heater hoses or any kind of by-passes? sometimes this causes problems (especially on AMC v-8's) because hot-water is getting recirculated and not run thru the radiator.

hope this helps! matt

Originally posted by Grendel
Sorry, forgot to mention.

Got a Warn X9000i in front.

Electric pusher fan (2900CFM), flex-a-lite mechanical puller (3100 cfm). No shroud yet. Not susre of radiator size. mepco says it keeps their jeeps cool in Utah in the heat. Moab tested.

Okay, that was a waste of my typing.. :flipoff2: shroud will help a bunch. One other thing, make sure you do not have a reverse rotation water pump for a serpintine belt on there..... Also what is the timing set at while idleing, 8-10? More than that will heat it up. Are you sure its not running Lean? Headers glowing? Restricted hoses?

And I agree with a previous post, the 4 cores are very inefficient, you may have to go to a 2 core aluminium....

HTH

does it puke? Is your sender/gauge good? An old Ramcharger I used to have would peg the temp guage, turned out the factory gauges didn't work with my engine swap. Hooked up okay,but read wrong. Just and idea.

I am running aftermarket Auto Meter gauges.

They're pretty reliable.

Fawker will run at 230 degrees no matter what you're doing. Doesn't matter what thermostat or radiator I run.

I had the same problem today. TPI 383, 700r4, mepco 4 core radiator, black magic fan (puller) hayden pusher. Still the fawker runs 230 - 235 :eek: that is when its 100 degrees out. WTF

Originally posted by jeepboyben
I see you are running a 4 core radiator. You might want to step back to a 3 core. 4 Core radiators are horribly inefficient. Many 3 cores cool better, because the cores in front of the others heat up the air passing over the cores behind them.

Ben

I disagree. If this was true, a 2 rod core would be more efficient then a three and a 1 rod core even more so. Yes, You could get to a point if the radiator was 2 feet think, that it would be the point of deminishing returns, but not a radiator that is only a couple inches thick. The idea is to increase the surface area of the water to air flow ratio for cooling. Sure, the back row will not cool as good as the front by a few %, but it not going to reheat the water. Com on!

Originally posted by orbitcat


I disagree. If this was true, a 2 rod core would be more efficient then a three and a 1 rod core even more so. Yes, You could get to a point if the radiator was 2 feet think, that it would be the point of deminishing returns, but not a radiator that is only a couple inches thick. The idea is to increase the surface area of the water to air flow ratio for cooling. Sure, the back row will not cool as good as the front by a few %, but it not going to reheat the water. Com on!

Actually, a 1 core probably is the most efficient. It just does'nt work because it lacks sufficient capacity.

I agree with the last statement. There is no way the air getting to the last core is going to be hotter than the water already is.
On the other hand, It may be that too many cores starts blocking air flow. I do'nt think 4 would do it though.

The only reason I could see that a 4 rod core would cool less would be because there wasn't enough flow to keep the water turbulent. Turbulent flow cools better then laminar flow. If the flow velocity was reduced because of increased volume, then the flow would become more laminar. However, since the flow becomes laminar because of reduced velocity, it stands to reason that the water spends more time in the tubes and should be cooled more due to longer air contact.

Ben asked if you have a shroud. Shrouds increase the mechanical fans ability drastically. Do you?

Do'es a shroud really help @ freeway? I do'nt have one but it only runs hot on long freeway trips. It seems like ther would be plenty of air going through.

At freeway speeds, I don't think the fan shroud has much effect since the air velocity at freeway speeds is most likely greater than what the fan can suck. At that point, the fan is not doing much and ram air is working for you. It seems weird that you don't have a heating problem on the trails.

I have the same problems. Doesn't really heat up unless I am at speed. I think I have a hose that is restricting. Any ideas on where to get a nice hose for upper and lower?

Doesn't really ever get to spewing.

Originally posted by Grendel
I have the same problems. Doesn't really heat up unless I am at speed. I think I have a hose that is restricting. Any ideas on where to get a nice hose for upper and lower?

Doesn't really ever get to spewing.

If you are overheating at speed then the fans/shrouds are limiting the amount of air that can pass thru or you have something blocking the grill.

The SPAL fan that I mentioned above has little rubber flaps in the shroud that open up at highway speed without that I would get warmer than usual at highway speeds.

HTH

Originally posted by orbitcat
However, since the flow becomes laminar because of reduced velocity,



Not to be an ass but flows do not "become more laminar". Flows are either laminar or turbulent and this is determined by their Reynolds number.

I'm a Chemical Engineer so I know fluid flow :D

Originally posted by orbitcat
If the flow velocity was reduced because of increased volume, then the flow would become more laminar. However, since the flow becomes laminar because of reduced velocity, it stands to reason that the water spends more time in the tubes and should be cooled more due to longer air contact.


The frictional losses incurred due to the longer piping would more than likelly not be enough to cause any significant velocity reduction.

Turbulent flow causes more molecules to contact the heat exchanger (radiator) surface as opposed to laminar. This is why Turbulent flow afford for more efficient cooling. To say that longer contact with laminar flow provides better cooling is ridiculous because you will not incur uniform temperatur throughout the fluid.

I also know heat transfer :D

Stop spreading this misinformation.

Run a fixed fan and a shroud, should be enough to cool it.

http://store.summitracing.com/default.asp?target=%2Fproduct%2Easp%3Fd%3D5%26s%3D 94%26p%3D3472%26searchtype%3Decat

I like the idea of flaps to let the air pass at fryway speeds. I might add that to my shroud.

Do a search, newbie! (Sorry always wanted to say that :flipoff2: )

Seriously now, here's a link to my own post on this a while back. Plenty of ideas in there. HTH

http://www.pirate4x4.com/forum/showthread.php?threadid=52686

Who's the newbie? Been around the board for 3 plus years. Just switched names and I am still not a newbie.

I read your thread when I did the search. You have a 258. I have a chevy 350, not apples and apples here.

Originally posted by Grendel
Who's the newbie? Been around the board for 3 plus years. Just switched names and I am still not a newbie.

I read your thread when I did the search. You have a 258. I have a chevy 350, not apples and apples here.

Damn how did I know you'd get your panties in a bunch about that newbie shite? Who cares anyway, it's the fawkin' internet.

As for the thread, some of that stuff doesn't apply exclusively to my motor. Forget about apples for a minute and see if you can't fix your cooling issue. Your hi-flow water pump could be doing to you the same thing my modified 'stat may be doing to me - letting the water run through too fast to get cooled. Maybe not, but it's food for thought. By process of elimination you just might find this problem.

(No I still haven't replaced that 'stat, had a frame to swap first. It's my next project. Hrmph.)

Bud, you assume allot. Who's saying I'm upset? You see any of these :flipoff2: :flipoff2: :flipoff2: or :mad: :mad: :mad:

Geesh.

Anyhow, I know cooling isn't rocket science. Just wondering if someone else ran into this problem.

Bigdude -

I might have mistated that the flow becomes laminar. I should have said the flow will become less turbulent as the velocity decreases. If you don't think this is true, then stand in a creek before and after a heavy rain and see if it isn't more turbulent.

I also didn't say that laminar flow with a longer contact time afforded better cooling. I was trying to say that when the velocity decreases, the contact time increases. I don't think you would see a big difference in cooling between the longer contact time and the decrease in turbulance in this application. I have seen many a heat exchanger that froze or overheated when the flow decreased. I would call that longer contact time.

BTW - I'm a chemical technician, so I get to see all the crap you guys put out that doesn't work like you say it should. :flipoff2:

Yeah I may have forgotten a smilie up there myself in my last post. Maybe one of these: :flipoff2: :D

I replaced every damn thing in my cooling system and it still runs too hot at freeway speeds. It should be the 'stat, but it's really just doing what it was doing before I ever touched it - except that now it takes a much longer trip and and it never gets quite as hot. The timing adjustment helped alot though (off by 5 frickin' degrees ... )

Now that I think of it, it also did it a couple of times in a drive-through ... does yours ever do that? Yet on trails and in the city it's cooler than cool, the only time it got a little hot was when I had to do the reverse-forward routine to get out of a mudpit, and it cooled down right away afterwards.

It ain't rocket science but we have a similar prob and don't know what it is. I'll do the stat just for the hell of it but doubt that that is it. Good luck with it.

Originally posted by orbitcat
At freeway speeds, I don't think the fan shroud has much effect since the air velocity at freeway speeds is most likely greater than what the fan can suck. At that point, the fan is not doing much and ram air is working for you. It seems weird that you don't have a heating problem on the trails.

That's what I thought. I don't have an electric fan to block flow, just a low profile winch. I'm not sure if I have a 180 or 195 deg. thermostat in it. If it's a 195, would going to a 180 help? I know it would start cooling sooner, but it seems like it would still reach the same temp in the long run.

I'llplay around some more and get back to you on this.

Problem is, I don't have a baseline for this motor. I bought it used and set up the way it is. So, I may even have a bad pump.

Originally posted by orbitcat

BTW - I'm a chemical technician, so I get to see all the crap you guys put out that doesn't work like you say it should. :flipoff2:

Bawahahahahahaha:D

Originally posted by orbitcat
Bigdude -


BTW - I'm a chemical technician, so I get to see all the crap you guys put out that doesn't work like you say it should. :flipoff2:

Thats typical of Chem E's:D :flipoff2:

Anyone know where to find the GPM and PSI for a water pump. I bet the pressure drop through a motor is huge.

Not to get back on the suject or anything, but I've read that the reason Aluminum radiators can cool better while simultaneously using fewer cores is because aluminum cores can be made thicker and therefore stronger than the brass and can therefore support bigger cores and that bigger cores (for whatever reason) cool more effectively.

Just what I read...

Jake

Originally posted by Jakesteramalamajama
Not to get back on the suject or anything, but I've read that the reason Aluminum radiators can cool better while simultaneously using fewer cores is because aluminum cores can be made thicker and therefore stronger than the brass and can therefore support bigger cores and that bigger cores (for whatever reason) cool more effectively.

Just what I read...

Jake

Its all about suface area:D