Yet another "My XJ Runs HOT" Post

[Roler]

Originally Posted by ruffy01

I had overheating issues plague both my XJ's at some point in time. I tried a number of fixes but inevitably the cure was to ensure EVERY component in the cooling system was healthy. The last issue I'd had was a new radiator cap from Supercheap wasn't doing it's job, replaced it with one from Bursons...problem fixed.
So even the most minor of components can screw you over!
You shouldn't need to go to extremes to keep the XJ cool, just the basics.

One incident that caused me some grief was after replacing a water pump the XJ started running hot, it had not run hot prior but the pump needed to be changed because it developed a leak.
I had another near new radiator handy, swapped it in and problem solved. The diagnosis was that the increased flow from the new water pump must have dislodged some crap in the block and clogged the existing (very healthy) radiator...Grrr!

In summary, what I'm saying is don't try fancy mod's to fix the problem, just go over all the factory components systematically and you will solve the over heating.
Good luck

Fully agree and basically says it all... A lot of cooling mods should not have to be necessary and are added whilst the primary cooling system isn't up to scratch (also the components that you think might be ok) and should be seen as bandaids to the real problem...and yes, the rad cap is often overlooked!
I recently had my (only 5 year old) copper core radiator fixed (3 leaks and turned out to be 70% blocked) as last step of the cooling system reconditioning (had only 1x overheating under the heaviest possible conditions, not even ran hot before that))...now it runs sometimes 91-92C, which is a temp that only just opened the thermostat...

[LuluBelle]

Thanks everyone for the input
My entire cooling system is NEW!
and clean as including all the rad air con rad and tranny cooler rad
2 years ago and 4000 klm ago I flushed the block and replaced the thermostat radiator and water pump
all highway driving as I live in Blackall its on the highway straight away 100 klm either way to the next town............and no stop start traffic in town
so one would think at 100 to 105 kph there would be plenty of air flow to keep it reasonably cool

then 2000 klm ago I had thermostat issues I replaced it with one from repco whick died after a week luckly I was in Brisbane so I changed that thermostat for this my 3rd thermostat which supposedly opens at 85 deg I changed the cover as well so there would be no chance of a leak I also changed out the ebay aluminium plastic radiator for a OEM radiator and bottom hose it ran a bit cooler on the way home but still hotter than I would of liked after all that $$$$$
still over the 100 mark whats the next mark on the dial 110? that's where it was staying
not much use in the last 12 months as we generally drive the PT around town probably 500 k in the last 12 months
all fluids are correct although I found I needed about 500 ml of coolant to top up after sunday
so you can see my dilemma all the cooling system is good?
I am going to run it in the yard to see if the electric fan cuts in ok but you shouldn't need that on the highway
Should You?
Is it the ElCheapO coolant from supercheap I use ? doesn't worry the PT and its a east/west engine it runs nice and cool
Should I try a expensive I bet you bute waterless coolant?
I really don't know at the moment

[oldon]

You might have to get a Scangauge/ Xgauge or similar so you can check the temp more accurately. Maybe one of those gadgets that talk to your phone. These things will let you check many other things also. Regards oldon.

[projoe]

as olden has stated make sure your gauge is not telling you lies I doubted my wrangler temp gauge for a long time so i bought a scan gauge & as i thought it was out buy a few degrees. now when you think that the dash gauge proper & the sender unit proberably cost jeep $1.50 you cannot after all these years expect it to be accurate.

[junglejuice]

I've had issues in the past with thermostats, particularly aftermarket units, I'm running my original t/stat now which is at least 12yrs old as that's how long I've owned it.
As you're in warmer temps now try taking the t/stat out and give it a run on the highway and see how it goes temp wise.
Also try and verify if the temp guage is working correctly and remember on a pre-update the temp sender for the guage is at the rear of the head, try measuring the temp with a probe and see if it roughly correlates with the guage.
As for the GC clutches, that's not a brand but a Grand Cherokee clutch, ie from a local Zg or a US sourced Zj unit.
As mentioned I think above lean mixtures will result in higher temps so try switch to petrol and see if the temps are similar under similar conditions.

On the highway the fan/s don't really do a lot assuming that there is no/little actual obstruction to airflow including through the condensor etc (not just things light driving lights etc).

Fancy coolant is NOT required for these engines, even on straight water or elcheapo pre-mixed coolant it should not give overheating issues if the "system" is "effective"...

Lastly, mods AREN'T a fix just a band aid/disguise....

[rustynuts]

All my cooling issues have been centered around the radiator cap.

[xjdavid]

Gas will run a bit hotter.

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