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Has anyone actually overheated?

over2land

over2land

NAXJA Member #1171
NAXJA Memorial Lifetime Member
Location
Green Valley, CA
I've been hearing horror stories, or at least allusions to, overheating issues in the XJ/MJ bodies with the 4.0.

I've got an 88 with a 4.0 and AC. Also, I live in the SW.

I fully plan on ditching the closed system in favor of an open one.

But beyond that, is there a NEED for anything else?

I mean, like electric fans, hi flow waterpump, etc etc...

Have any of you had problems with either boiling over, and or anything else?

Thanks.
 
last week I installed an ASC pump from autozone along with S belt, lower rad hose and 180* tstat. during the install I pressure washed the radiator (inside also) and "burped" the system while filling it. I wheeled for about 4hrs Monday with the temp guage below 1/2 way. Before the pump blew and was replaced I couldn't drive 5 miles w/o overheating. I figured it was the "heat defect" everyone yells about and without $500 to piss away I'd just have to deal with it. BTW, it's still the closed system.

-r0
 
The closed system works as good as the open. Just make sure it is tight and there are no leaks.
They all over heat if not mantained well.
I have the same set up...an '88 with the closed system, used to over heat all the time. I replaced the rotten Rad, replaced all of the hoses, and replaced the plasic cap (which is a dealer only item).
Do all of those and you will not need to monkey with a conversion.
 
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exact same story as The village idiot. and yes I have boiled the system before.hasta
 
over2land said:
I've been hearing horror stories, or at least allusions to, overheating issues in the XJ/MJ bodies with the 4.0.

I've got an 88 with a 4.0 and AC. Also, I live in the SW.

I fully plan on ditching the closed system in favor of an open one.

But beyond that, is there a NEED for anything else?

I mean, like electric fans, hi flow waterpump, etc etc...

Have any of you had problems with either boiling over, and or anything else?

Thanks.
Click to expand...
There is no "need" to ditch the closed cooling system. The open radiator is no larger and cools no better than the closed one.

I have an '88. Back around 2000 (or maybe 1999) I had a severe overheat on a hot summer day in a section of NYC where I shouldn't have been, except for being lost. I survived and the Jeep survived. Couple of months later the radiator sprung a leak, so I replaced it ... with another closed-type radiator. When I got the old one out and started looking, I would estimate that the cores were about 95% clogged with scale and "stuff." I have since made certain that only I add coolant, and that I use only distilled water in the coolant. No more problems, even in hot summer traffic or on hot summer trail rides.
 
Yeah I just swapped my fan clutch and thermostat with new ones and flushed and refilled my system with this cooling system cleaner schtuff..

Tonight I drain it and refill with coolant and distilled water...

When I pulled off the fan shroud and the manual fan it looked like the fan had hit the rad... plus all the fins on the back side of the radiator are so rusted that they flake away when you touch them.... So I decided not to pressure wash it.

cant afford a radiator right now or I'd put one in too.

The 160 deg thermostat should keep my temps low for now and when I put my lift and 33's on I plan to drop in a modine 2 row or whatever is the cheapest 2 row rad I can get my hands on along with a tranny cooler...

EDIT::

BTW I never actually boiled over or bursted a hose but I did see high temps on the guage that concerned me enough since I am taking a 12 hour round trip drive in the mountiains this weekend to pick up the aforementioned 33s

We'll see today when I do the second flush and drive it around to try and get it to over heat.
 
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Citat3962 said:
The 160 deg thermostat should keep my temps low for now
Click to expand...

Umm..no. I currently lack the ambition to explain why, trust me.

I have overheated mine to the point of not running, dry cooling system. Blew a plastic tank on the original radiator. Let it cool, fixed it, and all was well.

Rev
 
K... I'll explain my thinking..

Lower temp thermostat will be at full open at 160 degrees.

The coolant will start going through the rad at an earlier temp so the radiator has more time to cool the coolant and will have a larger range in which the thermostat is sitting wide open...

It will take longer to reach operating temperature with the lower temp thermostat...

I also hypothisize that since the opening in the lower temp thermostat is smaller than the one in the stock thermostat it should slow down the speed of the moving coolant allowing it to pick up and drop off heat more effectively..

All that said I didn't put alot of thought into it.. it was 12$ and I was flushing my system anyway.... The flush and the rust cleaner is probably going to be a bigger deal than the thermostat was..

or who knows I might overheat again on the way to dump the cleaner stuff out and fill it with coolant.. I'll be driving 5PM traffic here in about 30 min.. as much as I'd rather not if that's the case I'll drain it and whip out the capital 1 for a new radiator...

Just trying every cheap option before I go for the $100+ solution..
 
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I agree with Rev... the 4.0 is designed to run a little hotter than most and runs more efficiently when doing so. I put in a 180* and I run at a stable 195*. What I didn't mention was that when I opened the tstat housing to inspect the tstat there wasn't one. Trust me, stay in the 180-195 range.
 
Yeah I really have to wonder about the above "oldtimer" response... trust me...

Do you mean I should worry about my oil not getting hot enough>?

Or are you saying this isn't going to even affect my cooling issue>?

I'm fairly knowledgable about cars a simple explaination of your reasoning would be nice I'm not sure what you mean... (no need for the britannica here)

because if it's the oil not getting hot enough issue, then It's ok I'm not planning on running it like this for long... just til I get my trackbar LCAs and get my GTI emissions tested later this month so I can take the jeep down to put on the lift 33s and I guess a new radiator on.
 
Cool...

I figured heatsoak of the radiator had more to do with it than it actually does..

we'll see if the rad flush solved it enough to get me to durango then..
 
Wow, got more input than I expected. So it seems like most overheating is due to dirty/clogged rads, or failed pump. Not a defect in the stock system, but just negligence and or age. Good info, thanks.

Ok, here is where I'm coming from.

I just got the truck. It's got a closed system, the cap on the recovery bottle is shot, the hoses are soft, spongy, and flaking, when I drained it, ugly stuff came out. I also have my doubts about getting the hoses off the plastic bottle without breaking it (I have a previous history)

Some of the fins on my rad are hammered, and I'd simply rather put one with more rows in it.

On top of that, in the space occupied by the bottle on the firewall, I'd like to put a remote oil filter, and possibly an electric fan controller.

I really don't like the idea of burping the system.

So, for all those reasons, I figure I lose nothing but maybe an hour in trimming the rad core support to switch over. Since I am replacing hoses and so on anyway, why not? Also, I was told there are more aftermarket/hi-po rad options in the open category.
 
97148794.jpg



I don't know Anything about overheating.... :gag:

After this I ran slightly warm, until I had a chance to pull the radiator, have it rodded, flush the rest of the cooling system, and add a manual switch for the electric fan.

Now it runs consistantly at 210-215 when off-roading, cooler(around 195) when on the highway.

Basically, take care of the system and the open VS. closed thing is nonsense other than slightly eaiser maintence.


OMG, I just agreed with Sean, twice in one day.
 
Citat3962 said:
The 160 deg thermostat should keep my temps low for now and when I put my lift and 33's on I plan to drop in a modine 2 row or whatever is the cheapest 2 row rad I can get my hands on along with a tranny cooler...
Click to expand...
Wrong.

The purpose of a thermostat is to keep the temperature UP, nit down. If your radiator won't keep the temperature down to 195 or 180, it sure isn't going to keep it down to 160. Bad idea -- incorrect application of theory.
 
over2land said:
Wow, got more input than I expected. So it seems like most overheating is due to dirty/clogged rads, or failed pump. Not a defect in the stock system, but just negligence and or age.
Click to expand...
Or afailed (or failing) viscous fan clutch. If the temp starts to rise when stopped for a long light or in a line of traffic, and immediately drops to normal as soon as you get moving again -- look first at the fan clutch. It means the radiator will cool when there's air moving through it, but the fan clutch isn't allowing the fan to pull enough air when the vehicle is stopped.
 
I used to have problems with overheating. I used to have a bra on the front with a mesh screen over the grill. Would overheat on hills and especially during a snow storm. Soon as I took it off no more problems. It does get a little hot 4Wheeling but now to bad.
 
Another thing to worry about if the system is kept too cool is acid build up. At about 150* the water that condences in the block as it cools combines with the "lighter" hydrocarbons to form acids. If those are not completely evaporated and the particles heat cracked the molarity increases until it starts to cause premature oil aging and engine ware. As I understand it that is why newer engines are designed to run hotter.
 
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