Has anyone actually overheated?

[Roll-over]

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

The 4.0 only really needs to be burped after a coolant drain, and I'd burp an open system also.

 

[usmc_1371]

I have an 88 with a pretty built 4.0(soild cam ported big valves yada yada) and have blown pretty much every hose that can blow and never close to home. The first problem was just old hoses and worn out fan clutch. Added hood vents, new fan clutch and manul switch on the electric fan and new rad helped alot still closed system though. 160, 180, or no statt didn't make a diffrence execpt in mpg. Blew severl hoses in the snow with outside temps like 20 or less.
my .02
maybe this is why I haven't seen an xj in irap yet?

 

[RichP]

Closed vs Open cooling system really offers no great difference in cooling. In fact many of the new cars and trucks now have gone back to closed systems. As far as the pressure bottle, quadratec sells them, eagle has his own design that he built from parts, tank was from summit racing and I seem to remember the rest of the hardware came from local plumbing and hardware stores but his takes a normal pressure cap and the tank is aluminum, thin and tall.
I have a new modine coming today for one of our TJ's which developed a bad leak where the top plastic tank is clamped on to the core, probably broke it loose when my daughter broke that saturn in half...now that it is warming up the problem is getting more obvious.

 

[kubtastic]

Theoretically don't you want the engine to run as hot as possible to run most efficiently in terms of fuel temperature change?
(sorry for the hijack)

 

[Citat3962]

YUP.


Rev

I conceede.

you were right..

The cooling fins on my radiator were so rotted they flaked away at a gentle touch...

I was running hot again on the way to the garage to work on it..turned on the heater and it cools down immediately. So I figured that is a good indication I didn't have enough radiator cooling area..

SO I picked up a radiator at the Checker because it was the "CHEAPEST" It's not the GDI 3 Row it's the other one... 200$!
The good news is my jeep isn't over heating..

The bad news is I forgot to put my old thermostat back in so now I'm running at like 140 deg.....

Oh well.. sometimes you just gotta do it the wrong way to see your error...

I'll try to get the old one back in before I leave for durango so I guzzle less gas on the way.

thanks guys.

 

[RichP]

You need to cultivate some parts sources. I've gotten my last two modines for the TJ's for $135....same price for my 98XJ when that comes due which may be this summer just for preventitive maintenance. The rad is 7 years old and over 255,000mi on it. Going out to do my daughters now in a few minutes after it cools off from her driving home from school...

 

[thisfirstlove]

i overheet all the time when im wheelin' i just got used to "taking a rest"

 

[RichP]

Well, just got done putting in the radiator in my daughters TJ, burped the system and let it run, did a test drive. Engine sits right at ~195, upper hose gets hot and the top tank stays cool enough to touch, holds pressure for about 20 min after shutoff. Made a quick trip crawling up a steep power line trail in 4lo and it stayed rock solid on the temp both up and down. Ran it pretty hard on the local hiway, so far so good. Only issue was the damn speed nuts, ended up cleaning out 3 parts store for those 1/4-20's, each had two in stock. This is the same rad we put in my sons TJ. I hope I have the same results when I do my XJ.
The old one looked good from the front and except of leaking around the top tank it looked OK, another story totally after I got it out, the fins in both upper back corners and almost all the way across were totally rotted out. I think I'm going to need to pull my XJ's fan shroud and get a closer look at the backside of my rad. If it is anything like hers I figure I'm going to do mine sooner than later.

 

[BruteXJ]

Ok, I need some clarification.

I read most if not all of the tech articles on this site to gain more knowledge about my vehicle and learn what might go wrong first, and how to diagnose it. I'm not unfamiliar with a wrench, but I've only owned an XJ for a year or so, ask me about the 258 in a CJ-7, and I'll sound a lot smarter.

Do ALL XJ's overheat? Or does this pertain to a few years of production? I've read all about installing hood vents, swapping cooling systems, etc and always wondered why. My '99 Sport always runs normal, even when crawling over obstacles, or waiting for an hour with the AC on while someone else does. Granted, I regularly maintain my vehicle, and know the previous owner did as well. Is it a model issue, or a maintenance issue?

 

[RichP]

No, they dont all overheat, I too sit in the woods with my A/C on BUT I am also fastidious about maintenance. My system has always been flushed yearly and new foolant with distilled water added that I check with a prestone mix tester before I replace it. It is all based on maintenance and how well it's taken care of. I figure at 300,000 I may do the water pump but that will be next summer. This summer I'm doing the radiator and hoses,*might* do the pump while I have it all apart, *might* do the fan clutch, not sure yet, but I do know I want it to continue running as well as it did when it was new. I'm over 255,000mi now.
Where you are located you also don't have to deal with the winter salt and chemical mixes they use up here in the NE, that can take a toll on a radiators outside.

 

[BruteXJ]

We get salt and chems, but not as often. Thanks for the reply.

 

[Rev Den]

They only overheat if not maintained. I am not at all fanitical about maintaining mine, fluid change, flush, refill, and it does just fine.


Rev

 

[MudDawg]

I have a newly rebuilt engine in my MJ because the previous owner didn't maintain the cooling system...after the rebuild, with a new modine rad, cap, t/stat, hoses etc....it runs at a normal 210 with the a/c on in traffic.

The oil/temperature thing...if you don't run the oil hot enough and/or for a long enough time to evaporate the water and aromatics you get sludge. The worse sludged engines are out of Granny's car...the cleanest are out of commercial vehicles where they run for hours on end.

 

[BruteXJ]

Aromatics.....hmmmm.

I get what you mean, but it brings a to mind a mental image of soaking in a hot Georgia red clay mud-bath listening to country-rock surrounded by Daisy-Duke look-alikes with the "aroma" of motor oil piped in for ambience....or maybe that's just me.

 

[Citat3962]

woah nice imagery

 

[RednsilverXJ]

yep, did it with a stock open cooling system, 4.0L, 5sp, re 5.5 xdla, 35's.. 3.07 grs.. caused due to failure of electric fan temp switch / relay, hardwired fan to run whenever ignition is on, didn't do it again. if you elect to maintain the factory cooling system i'd highly recommend a fan switch override, available from ebay usually or if you want to do the work yourself it's not hard, better to be in control of your rig than letting a computer decide what to do, we know how well they work.