XJ Radiator/Cooling stuff

[junglejuice]

The thing is even if the coolant is wrong it will still not behave the way it is being described, there is something very wrong with this cooling system and until that is found replacing what may be a perfectly adaquate radiator is pointless.
You need to find out which part or parts are faulty before considering upgrades, check your thermostat as it is running too cool at speed which is a big no-no for your engine as well as your fuel consumption, check that the thermo fan operates correctly, it should switch on just over the 100 mark without the aircon on, check that the thermo fan operates with the aircon running.
You would feel very ripped off spending hundreds of $$$ to find that it is the thermostat....
Let us know how you go..

[bruggz351]

As above. This mob know their XJs. I've literaly just spent thousands chasing a over-heating issue, but mine had very odd simptoms. Just couldnt nail a cause, so I had to trial n error it. Mine turned out to be a cracked head, though I dont think thats your problem, yours also runs too cool. My vote also would be to check the thermostat first. And test the senders.

cheers

[MudMonkey30]

Thermostat
&
clutch fan
&
check your thermo fan is working properly, next time it goes over 100 pull over and pop the hood to see if it is!

BIG Reminder!!!!!
Only fix 1 thing at a time!!!!!
Will possibly save you money in the long run and will help let you know what is the main cause.

[Siggers]

Cheers guys, all very sound advice, I should hopefully have some time tonight to have a look over some things, and hopefully the weekend although I have a big show to run

[Siggers]

Ok so I have checked the aux fan and that comes on, I drove for about a minute and half with the brakes on giving the motor hell to get the temp up, got up to the 3/4 mark... and when I start reving the clutch fan spins I can hear it, but after a little bit even on constant revs it slows down... Any thoughts? i will be pulling the thermo stat out tomorrow and flushing the system...

[FredE]

If you are thinking of a new radiator look at the Adrad 3core has more coolant capacity and larger cooling surface Take your to a radiator repairer they will remove the end tanks and clean the tubes for around $100 as opposed to a new one for $400
If your temp is down to 80 then that information is being sent to the temp guage and the computer which cause the engine to run rich as it thinks you are still warming up so check out your thermastat
All the info that the boys above is good I think that we all have had to sort out overheating problems

[jakob292721]

agree with everyone. my problem was that when i get mine, the coolant was nice and green inside the cap, but was overheating. ended up cracking the head and having to redo it. after pulling it all apart, found that the previous owner had a mechanic replace the radiator and top hose to fix. (didn't) fins on water pump were completly gone, and they didn't change the bottom hose(too hard!?) the spring in the bottom hose was rusted and was partly blocking the flow, and no fins weren't helping. so for the sake of checking the water pump and bottom hose, they could have saved the old radiator. good luck. i agree with the check one thing at a time idea too. btw, it now runs about 100. gains slightly to 105 or so, but only when doing comps or rock crawling. i think someone has changed the timing for the electric fan, as it cuts in as soon as the aircon is on, evan when the engine is cold? it runs for about 10secs then stops for about 20secs? anyway, works, i'm happy with it for now.