4.0l XJ overheating? Start here - the basics!

[Geejeep]

Originally Posted by junglejuice

Yes it can, do a search for this as it has been covered before although if the cooling system is in good nic then it shouldn't go over 95 in traffic...

Thanks, found it here for anyone else considering the same:
http://www.go.jeep-xj.info/HowtoTaurusFanInstall3.htm

[shakes]

Being it was 41°c here, and I was crawling in peak hour the cooling system got a damn good workout. It sat solid at the first line after 100 on the gauge until we started pointing slightly uphill. Dash went nuts and it jumped up to the first red line.. sat solid there for 10-15minutes. we crested the 'rise' and I turned the heater on at the same time from the AC. Within about 3 seconds the temp dropped back to the first line and sat there. Until home (another 20 mins)

Now I'm home the bonnet was far to hot to grab with bare hands. the overflow was full but not overflowing. The overflow is also literally boiling (i get the pressure raises boiling point bit)

How normal is this for the XJ? a few months ago now ~5000k it got a new rad/clutch/t-stat/waterpump/hoses/cap. I'm guessing to improve on what is there now is the ac switch, trans cooler and what else?

[shakes]

Have I got this right? it was bubbling cause the inlet is at the base of the overflow.

My best explanation was a random air bubble working it's way through... mixed with a somehwhat dodgy rad cap, the temp slammed down when it opened released the pressure and partial air lock ??

[eksjay]

What does it mean, if the top large hose coming from the radiator leading to the front of the engine (I assume the water pump) has expanded in places?

Does it mean that the water pump is on the way out or has died?

There is no sign of a leak so far.

I opened the bonnet after experiencing a 115 deg C climb which came back down to 100 deg C when the aircon was switched on - a departure from the regular 95 - 105 deg C range.

Is there a blockage somewhere that is causing this expansion?

I haven't really noticed the expansion of the hose before but only did so when I hadn't switched the aircon on and the car was still hot.

The radiator was changed about 7 years ago, not that it needed changing back then, but the stealer could not find the source of a coolant leak - it wasn't the radiator.

What is the typical cost of an XJ waterpump and thermostat and labour?

[eksjay]

Originally Posted by eksjay

What does it mean, if the top large hose coming from the radiator leading to the front of the engine (I assume the water pump) has expanded in places?

Does it mean that the water pump is on the way out or has died?

There is no sign of a leak so far.

I opened the bonnet after experiencing a 115 deg C climb which came back down to 100 deg C when the aircon was switched on - a departure from the regular 95 - 105 deg C range.

Is there a blockage somewhere that is causing this expansion?

I haven't really noticed the expansion of the hose before but only did so when I hadn't switched the aircon on and the car was still hot.

The radiator was changed about 7 years ago, not that it needed changing back then, but the stealer could not find the source of a coolant leak - it wasn't the radiator.

What is the typical cost of an XJ waterpump and thermostat and labour?

To clarify - the hose had expanded between the sleeve protecting it from the pulley and the water pump. The rest of the hose was its regular size. I had another look at it now that the engine temp is cooler and the area of expansion went back to normal size.

At the time I stopped the engine running, I could smell a disc brake type smell coming from the wheel area but it could have been the disc brakes.

[bruggz351]

I'd be replacing that hose man. Sounds to me as though it's gone soft.
Did it blow up, like a balloon?
Was it the top hose or bottom hose?
Does the overflow work? Perhaps the radiator cap isn't releasing pressure.?

[eksjay]

Originally Posted by bruggz351

I'd be replacing that hose man. Sreplacements to me aTelco. ugh it's gone soft.
Did it blow up, like a balloon?
Was it the top hose or bottom hose?
Does the overflow work? Perhaps the radiator cap isn't releasing pressure.?

Its gone soft between the pulley and the engine. I bought A new top hose from repco but have not installed. Yes, the existing hose blows up like a balloon when hot, and deflates when cool, but remains soft in that section after deflation, while the rest of the hose is firm. I am guessing the bottom hose might have same issues. Will get a thorough cooling system check done.