Select to expand quotemineral1 said..
Thermostat I guess was the problem, they get tired
Realistically a change every 12 months, along with a coolant kicker or change. Don't listen to hogwash about "Oh it must run coolant, otherwise it wont cool" That's a load of crap. Use a good coolant, and top up with de-mineral water (the stuff you use in the clothes iron ) Dont mix coolants brands, if you can help it, some don't like each other
Change the belts, as some when get got, slip over 20% and wont drive the fan at rated speed.
A thing I learned a few years ago was that the coolant was mostly to stop corrosion of the aluminium radiators, as all the different metals created a potential in the cooling circuit. After a few year you get holes happening. Well at least that's what happened to mine.
I can't image there is much cooling difference between water and coolant if your cooling system is pressure tight.
Select to expand quoteR0CKH0PPER said...
Okay, might be able to add here.I've owned a 97 jeep xj for 3 years now as my secondary weekend hack vehicle. See's a lot of off road, and surprisingly good. I've snatched a late model landrover and a 2012 hilux so far. Just the other week I watched a flash navara sink to the diffs on the beach, while I cruised past still running 40psi. More to do with experience than anything mostly.As for the overheating, they are famous for it. Mine always used to get hot, so I researched the hell out of it, and as it is only a hack, just did cheapo backyard jobs.First, I wasn't sure wether my thermo was kicking in or out......So I wired it direct into the cab with a switch....so I know its on.My air con wasn't working, so I pulled the condenser out in front of the radiator...opened up more air flow for the radiator..definitely helped.
Few months later I worked out I could squeeze 2 10 inch thermo fans in the now empty space, and also wired them into the cab with switches. Problem solved.Mine is always good on the highway, just gets hot offroad ( or stop/start driving if your in the city I'd assume). Though a while back I did notice temps climbing more than usual on the highway. Researched again, read about the viscous fan clutch and checked it. When you check it, car must be hot when you turn it off to try and spin it, so that you know its supposed to be engaged. I could spin mine, so I was pretty sure that was it. The other way to test it is to use a rolled up newspaper, and try gently stop the fan when its hot. Wouldn't recommend it really, although I tried it anyway, and it definitely proved the clutch wasn't working.I replaced it with one of ebay (about $80) and temps dropped back. All good. For about 2 months, then started rising again. I couldn't believe that I did the tests again, and sure enough, the fan clutch was gone. I couldn't be bothered with trying to get a refund through ebay with all the postage etc. Bugger it I though, and I welded my original solid, so its always engaged...permantly. I simply figured if the fan makes that much of a difference to temps when its not engaging, it must be engaged MOST of the time. Did that a fair while ago now, and so far so good, no problems....other than a bit more fuel usage :/
I also put to decent sized scoops in the bonnet to for more airflow, it gets super hot under there. You can also get slightly longer bolts for the bonnet and add some washers so the rear of the bonnet has a 5-10mm opening, apparently also makes a big difference.Just tonight, I was looking at GO JEEP website, on how he removed the viscous fan all together, and replaced it with a quality electric one. Has to be a pretty good one that moves around 2500-3000cfm of air, not some ebay spec chinese crap. Seemed to work extremely well for him, and also gained power and better fuel economy from ditching the viscous fan.Last 2 tips are : I found at standstill, if you put it in neutral and hold the revs on slightly, temps drop, and if all else fails...heaters on full bore fixes it everytime, however unpleasant for the occupants.Wealth of information I found mostly within these 2 sites...
I've linked it straight to the XJ section...ask away there or use the search function...theres a decent thread stickied to the first page about overheating.www.ausjeepoffroad.com/forum/forumdisplay.php?f=123
Any go jeep, a man who knows his xj's very well, and spent wayyyy too much on his. Awesome ideas in there though, and good reading about the overheating and various solutions as well as install guides...jeep-xj.info/ They may not be the ducks nuts, and also cop a bit of a hammering, but mine has served me well, got me to some good places, and for $2500, I can get a dent here or there, drill holes through the roof to mount lights and still not care to much.Its not about the car...Its about the journey!
Thanks mate really good info am going to put spacers to lift the Bonnet as that's a quick simple job. Was looking with my father inlaw today who is a retired panel beater he doesn't see much room to fit an extra fan infront of the radiator there but we going to measure it up see what size would fit.
One other thing, anyone ever put a can of chemi weld into the system?? There are lots of dried white dots all over the engine area that only appeared after last time it over heated and father in law swears from memory that is what this stuff looks like dried. Coolant did spill out the top radiator cap.
So that tells us that she has had a cracked head long before I got it and has held up since.
We are thinking that maybe we throw a can Into it.
Whats peoples thoughts??
I know a lot of people are saying 90-100 is normal running temp for these things but this old girl has had a rough life and with that many kms on the clock in my mind getting it to reduce that little bit more in running temp might be just a little bit less stressful on the running of it. I dunno maybe that's just stupid talk that makes sense in my head haha.
It just smells like its cooking all the time and I'm not confident in city traffic it's going to stay steady at the 95-100 even after I've replaced 3 of the main parts.
Checked fan it doesn't spin free it stops after 3/4 to one turn. Def does come on: should I leave it or should I replace it? Piece of mind knowing a new fresh one is in there with a new clutch?
With the air conditionding condenser in front of the radiator, I'd doubt you would get thermo's on the front. Shame, because 2 thermo's there definitely solves the problem. At that age, I cant see chucking a can of chemi weld in being disastrous.90-100 deg is normal running temp, so don't stress it, but I know when it climbs, it climbs quick, hence its good to have those extra thermo's to flick on if you have them.
Select to expand quote
AndyR said..
Checked fan it doesn't spin free it stops after 3/4 to one turn. Def does come on: should I leave it or should I replace it?
Even when rooted the viscous hub will 'appear' to be OK.
The 2 that I had on 'passed' the newpaper/water/grab it tests.
The only true way to to test it is to take it off and see when the valves open. (Putting it on a pot of boiling water)
orrrr replace it with a new one ;)
For the 2 fifths of f**k all it costs for the silicon oil, it will prove it.
Select to expand quotesotired said..mineral1 said..
Thermostat I guess was the problem, they get tired Realistically a change every 12 months, along with a coolant kicker or change. Don't listen to hogwash about "Oh it must run coolant, otherwise it wont cool" That's a load of crap. Use a good coolant, and top up with de-mineral water (the stuff you use in the clothes iron ) Dont mix coolants brands, if you can help it, some don't like each other Change the belts, as some when get got, slip over 20% and wont drive the fan at rated speed.
A thing I learned a few years ago was that the coolant was mostly to stop corrosion of the aluminium radiators, as all the different metals created a potential in the cooling circuit. After a few year you get holes happening. Well at least that's what happened to mine.
I can't image there is much cooling difference between water and coolant if your cooling system is pressure tight.
back in the 90's i had Tarago with just your problems. those white dots are corrosion in the head .
my mechanic was an ex toyota man and he explained that the alloy heads required an anti corrosion tablet to be dropped into the radiator at each sevice .
another mechanic i knew at the time said he'd never heard of the tablets.the tablet disolves and prevents the head pitting. once the head pitted it was all over. the other item that also corroded was the heater radiator as the coolant would sit without flowing most of the year and devlop pin hole leaks.
thats exactly what our commodore did TWICE
What do you mean by the head pitted??
So update I've driven it to and from work last three days in heavy traffic Scarborough to Bris CBD and return. Driving for over an hour each time start stop at traffic lights and slow moving along the high way.
The the gauge it's sitting happily between 90-100 more like 95. Car seems to still have power on take offs etc not sluggish at all. Do have the aircon runnin on low the high time and can hear the themo fan cut in and work. Temp hasn't climbed over 100 yet. Engine still feels like it's bloody hot and working way to hard though.
I'm slightly confident that the new radiator new t-stat and new water pump has resolved any over hearing issues and is keeping it running at a steady temp for now. Though it's so hard to just think all is good and not think while sitting in traffic is it just going to blow and stop and start steaming out again.
I still in my mind think it would be better if it ran just that little bit cooler so when it is really labouring it won't tip over the edge like before
Does your jeep run an auxiliary engine oil cooler similar to many Toyotas?
The Tojo's engine oil cooler takes oil from the oil pump bypass valve gallery, and cools it before dumping it back into the sump.
They are a pretty small cooler - and only cooling oil that is bypassed and not filtered - but it helps.
If your jeep has a similar cooler fitted, you could easily fit a larger capacity cooler to give it more capacity / cooler engine oil.
If your jeep doesn't have a cooler like this, you can get aftermarket adaptors that fit between the block and the oil filter - then you run a remote mounted cooler - again giving greater oil capacity and cooler engine oil.
stephen
Edit.......something like this:http://www.ebay.com/itm/UNIVERSAL13-ROW-AN-10AN-ENGINE-OIL-COOLER-Silver-FILTER-RELOCATION-KIT-Black-M-/151515344316
The jeep doesn't run one I don't believe unless it's hiding somewhere but it sounds like something to look into
Select to expand quoteAndyR said..
What do you mean by the head pitted??
So update I've driven it to and from work last three days in heavy traffic Scarborough to Bris CBD and return. Driving for over an hour each time start stop at traffic lights and slow moving along the high way.
The the gauge it's sitting happily between 90-100 more like 95. Car seems to still have power on take offs etc not sluggish at all. Do have the aircon runnin on low the high time and can hear the themo fan cut in and work. Temp hasn't climbed over 100 yet. Engine still feels like it's bloody hot and working way to hard though.
I'm slightly confident that the new radiator new t-stat and new water pump has resolved any over hearing issues and is keeping it running at a steady temp for now. Though it's so hard to just think all is good and not think while sitting in traffic is it just going to blow and stop and start steaming out again.
I still in my mind think it would be better if it ran just that little bit cooler so when it is really labouring it won't tip over the edge like before
The engine is going to run at the temperature the thermostat is set at. Unless there is a pressure problem, it will open and close the thermostat to keep that temperature. If you blow more cool air through the radiator or blow air more often through the radiator, it is not going to make any difference at all unless the thermostat thinks the engine is too hot. (I.e. there is nothing you can really do)
Do you have any idea what temperature the thermostat is? Usually the manufacturer sets these at a value that keeps emissions and economy at reasonable values without overstressing the cooling system.
You are probably just being paranoid after your initial problem, but it could keep running perfectly for the next ten years, or die tomorrow, if that sets you at ease 
How are you gauging that the 'engine feels hot'? Does the gauge creep way past where it sits once the engine has warmed up, or does it stay pretty much in the same spot?
If you have a leak in pressure, your engine could go from 'cool' to over heating in the blink of an eye. There is not much you can do when you have a leak. Pressure loss means the coolant boils at a lower temperature and a boiled coolant, AKA steam, is not very good at getting rid of excess heat. All you can do is stop the engine.
Did you replace the hoses as well? I replace them as a matter of course when changing water pumps or the radiator, but some people keep the old ones, and like anything they wear out.
You see a lot of hot mums dropping their kids at school and doing shopping in shiney unscratched jeeps....makes me overheat.....just saying.
They do have those over sized cup holders that suit the $10 double shot lattes with a hint of vanilla and twist of lemon which seem popular with the jeep crew....
just saying again,,,,,,,if you read anything into that,,well,, thats your own opinion,, not mine,,,,,,,you stereotype judgmental people should stop it ah. 
YOU BOUGHT A What.TF.?????????????????????????????????????????????????
Hope his helps.
So over a month on now and no drama what so ever. Stoked with the work that northside radiators did in Brissy.
Been driving in city for a month now and she is sitting steady on 90-95 so I'm happy.
Going to do some more upgrades later this year so I can get it back off-road can't wait
Just to add now I have seen they are "under coolant systemed" - in addition to aftermarket radiator etc, perhaps Water Wetter would help.
Made by Redline race oils, it helps heat transfer from metal to water (and then the the water to metal)
Worked fkn awesome in race cars we used to run it in...... a good 6-10deg drop in coolant temp
Select to expand quoteMark _australia said..
Just to add now I have seen they are "under coolant systemed" - in addition to aftermarket radiator etc, perhaps Water Wetter would help.
Made by Redline race oils, it helps heat transfer from metal to water (and then the the water to metal)
Worked fkn awesome in race cars we used to run it in...... a good 6-10deg drop in coolant temp
Agreed on that one, we used to use it in dirt bikes, works very well
If it's overheated that means it actually started..which is more than can be said of most jeeps. Count yourself lucky sir. (From a former jeep owner)
Select to expand quoteAndyR said..
what exactly is it? something you add to the oil??
no, to the water :)
basically its just flash detergent - it makes the water have better contact with metal surfaces and therefore conduct the heat away better.
In your application, it would simply run cooler.
Select to expand quoteMark _australia said..AndyR said..
what exactly is it? something you add to the oil??
no, to the water :)
basically its just flash detergent - makes the water have better contact with metal surfaces and therefore conduct the heat away better.
In your application, it would simply run cooler.
Doesn't sound too dodgy.
No, wait...
A mirror and some smoke perhaps?
^^^ my turbo 4 ran 18deg cooler, so I could run more ignition advance as a result.
You need to look at the test numbers before taking the mickey.
Have a gander at this cooling method
offroad80s.com/misting-cooling-sprayer-install-t12825.html
Select to expand quoteCassa said..
Have a gander at this cooling method
it wanted me to sign up to have a sticky beak........Sandwichmaker said no more signing up for dodgy forums
Probably the "olde schoole" fix that can get you out of strife - windscreen washer pump and spray nozzle [garden retic mist sprayer] hooked up to a water drum stashed someplace on board.
When the temp. gauge climbs, hit the switch and spray water onto the radiator.
It can be surprisingly effective!
Similar can be done with water injection as it lowers engine temp and stops pinging.
We used to use either manifold vacuum to suck water into a feed block under the carby [remember carbies?],
Or a windscreen washer motor to feed water into a spray jet up above the carby.
My 3 litre Capri had the water tank under the passenger seat, and it fed both the carby / carbies as well as the water cooled brakes.
Later - my twin cam Fiat's ran the same system of water injection through the webers.
One of the Fiat's had a cylinder head [and 2 x combustion chambers] that were mostly made of devcon and it was still being driven appropriately [thrashed] for years after I gave it to a mate.
Over the years I did similar to a few other vehicles that suffered from pinging and overheating, never failed to solve the pinging and greatly reduced overheating.
stephen
Select to expand quotesn said..Cassa said..
Have a gander at this cooling method
it wanted me to sign up to have a sticky beak........Sandwichmaker said no more signing up for dodgy forums
Probably the "olde schoole" fix that can get you out of strife - windscreen washer pump and spray nozzle [garden retic mist sprayer] hooked up to a water drum stashed someplace on board.
When the temp. gauge climbs, hit the switch and spray water onto the radiator.
It can be surprisingly effective!
Similar can be done with water injection as it lowers engine temp and stops pinging.
We used to use either manifold vacuum to suck water into a feed block under the carby [remember carbies?],
Or a windscreen washer motor to feed water into a spray jet up above the carby.
My 3 litre Capri had the water tank under the passenger seat, and it fed both the carby / carbies as well as the water cooled brakes.
Later - my twin cam Fiat's ran the same system of water injection through the webers.
One of the Fiat's had a cylinder head [and 2 x combustion chambers] that were mostly made of devcon and it was still being driven appropriately [thrashed] for years after I gave it to a mate.
Over the years I did similar to a few other vehicles that suffered from pinging and overheating, never failed to solve the pinging and greatly reduced overheating.
stephen
Just to go off on a tangent, when I was rebuilding my Escort motor, I sprayed a hose into the intake manifold while it was running in order to clean the combustion chambers of carbon. It was surprising how effective it was and also in the amount of water you could feed into a running engine without stalling it or breaking it. When I pulled it apart, there was no carbon at all on the cylinder head or piston. I probably wouldn't do it to an engine I really wasn't going to rebuild, but it sure worked well when I tried it.
I wonder why Jeeps seem to have a marginal cooling system. With so many alternative radiators that could be made to fit or even custom radiators, you would think it would be easy to solve these problems.
Select to expand quotesotired said..
when I was rebuilding my Escort motor, I sprayed a hose into the intake manifold while it was running in order to clean the combustion chambers of carbon. It was surprising how effective it was and also in the amount of water you could feed into a running engine without stalling it or breaking it. When I pulled it apart, there was no carbon at all on the cylinder head or piston. I probably wouldn't do it to an engine I really wasn't going to rebuild, but it sure worked well when I tried it.
I'm not surprised there was no carbon - you just steam cleaned the combustion chambers.
Dunno if I would use the garden hose though.......
Another similar DIY fix you don't see so often anymore is mixing Redex with water, 50/50 in a beer can, bumping up the idle and tricking the mix into the carby.
You would need to keep blipping the revs to keep it running, and when you were done you had just de-coked the engine, and then pulled the plugs and poured a little Redex into each cylinder and left it over night.
Next day, you draped rags over the plug holes, spun the engine over with the starter to get rid of excess Redex, then refitted your cleaned and re-gapped spark plugs to the engine, started it up and held it at around 2500rpm until it ran smooth - then took it for a nice long drive - preferably at night because it would smoke like a chimney for a few miles.
Doing this got rid of any remaining carbon in the combustion chambers, valves, and around and behind piston rings.
Engine would run much better, compression lost from gummed up piston rings was usually regained.
We did this to a Gemini which had no compression in one cylinder, and between 50 and 120 in the others - the young lass that owned it had been told by her mechanic that it was worn out, had a holed piston and the engine needed replacing [which she could not afford]
After the Redex and water, 165+ in every cylinder and one very happy uni student.
stephen
Select to expand quotesn said..sotired said..
when I was rebuilding my Escort motor, I sprayed a hose into the intake manifold while it was running in order to clean the combustion chambers of carbon. It was surprising how effective it was and also in the amount of water you could feed into a running engine without stalling it or breaking it. When I pulled it apart, there was no carbon at all on the cylinder head or piston. I probably wouldn't do it to an engine I really wasn't going to rebuild, but it sure worked well when I tried it.
I'm not surprised there was no carbon - you just steam cleaned the combustion chambers.
Dunno if I would use the garden hose though.......
stephen
I did this on an engine that I wasn't worried about, and I was curious as to whether it would work. It is a bit surprising how much water an engine can ingest at a decent rpm without problem.
I did this after reading a thread about it on aus.cars or rec.tech.auto (in the days of network newsgroups on the internet) and I was pretty sure it was going to work. I suspect its the temperature difference that causes the carbon to come off of the cylinder head.
I have never heard of Redex, but I wonder if you get a similar result if you use just water?
Interesting story about the mechanic claiming there was a holed piston. I suspect that this is not very common at all. You would think there'd be a significant difference between a hole in a piston and just a very low cylinder pressure. I remember rebuilding a 2L escort motor and finding part of the crown had disappeared, but it never seemed to be noticeable in performance when I was driving it.
Select to expand quotesotired said..
I have never heard of Redex, but I wonder if you get a similar result if you use just water?
Interesting story about the mechanic claiming there was a holed piston.
I remember rebuilding a 2L escort motor and finding part of the crown had disappeared, but it never seemed to be noticeable in performance when I was driving it.never heard of Redex......that's almost un-Australian!
They were the major sponsor for the "REDEX Around Australia Trials"
Admittedly a long time ago - and the quality of fuel and engine design have come a long way since then.
Using REDEX to de-coke an engine was much easier than taking the head off every time the carbon built up.
As for the Uni chick and the mechanic telling her the engine was knackered- I suspect he was trying to take her for a ride and flog her a jap import motor.
And your 2 litre escort's performance, well........it was a 2 litre escort after all. 3 or 4 cylinders wouldn't have been much different
stephen
