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.

R0CKH0PPER 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!

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?

sotired said..





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.

AndyR 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

sn said..
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

Mark _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

AndyR said..
what exactly is it? something you add to the oil??

Mark _australia said..


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.

Cassa said..

Have a gander at this cooling method

sn said..








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

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.

Cue the misting kit. I'd read a bit about them, seen different setups and scoped out my own rig to see what would fit and where. There were 3 main components needed:
1) Water tank
2) Water pump
3) Sprayer jets

So, armed with a length of 100mm PVC and a few bends, it was time to get building.

The tank sits between the slider and underside of the floor on the drivers side. I fitted the pickup at the rear so the pump could scavange all the water even when low while heading up hill, where I'd need it the most. Total capacity is bang on 10L

A water pump is mounted in the engine bay. Garden hose connects the tank to the pump, with garden hose out the other side before being reduced, using a combo of brass fittings, to fit the 4mm plastic irrigation line used on drip feed systems etc. The pump is activated via a switch on the dash. Nothing fancy for now.
<div>Removing the support panel in front of the rad, the 4mm line is secured to wiring harness underneath. Using a T and L bends, there are 2 sprayers about 200mm from each end of the rad that hang down about 150mm. I used brass spray jets that give a 360deg spray pattern.



RESULTS:
I've run this setup most of this summer now and it's been awesome. I have the WatchDog temp gauge set to alarm at 95deg. When I run the sprayer for 20-30sec, the temp drops back to high 80s within 1min. I was surprised how quick it works. Sometimes just 10-15sec is enough to take the edge off. The sprayer really pumps the water out so if you leave it on by accident, you'll run out of water pretty quickly, as I've done a couple of times.

Filling the tank is easy enough at home with a hose. When away in the scrub I use a 1.5L water bottle filled from my main water tank. Clean creek water will also work. Most weekends away 10L is heaps, but that can vary greatly on how hard the terrain, ambient temps and engine temps. On a 2 week trip in the VIC high country at Xmas, I filled it once after the original fill, and it was used pretty regularly.

sn said..




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

sotired 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.