I'm Hopeing this is not a Head Gasket

[LuluBelle]

thanks for all the responses I am using a little coolant prob 500ml every month in the overflow tank there are no mad bubbles in the rad I have a new cam sensor and up stream oxy the one in the cat is old knowing my luck it will be a tiny crack in the head $$$$
what I am thinking of doing is when cold take the plugs out look at them then get a drinking straw or 2 try and taste any coolant in the cylinders I dunno if it will work but worth a try
I will have a look at the camshaft sensor drive to see if it is worn
other than that I will keep everyone posted
I really wanted to spend my pocket money on new bushes but.............now the fridge is playing up how am I going to get my HomeBrew COLD!

always something
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[layback40]

Doesnt sound like a crack. If you think it is though you could try a Chemiweld treatment. It works very well on cast iron heads.

[awg]

what the other guys said

* Chemiweld works great if you get it early, not so good once things have progressed

* warm the motor without rad cap, on flat ground, add water to near top of filler neck,,,if it bubbles, there is a leak

* check inside oil cap very often for creamy color

* the coolant test kit is only about $50

* if you have an inspection camera, the top of the affected piston will be a different color, as will the plug, but harder to notice (if coolant ingress to combustion chamber)

[LuluBelle]

OK......UPDATE
I took 3 and 4 plugs out 6000k old perfect! nice grey no carbon the porcelain was a bit yellow on the electrode and a little up the stem heat all good I thought oil fine oil cap fine no milky shit needed about 300 ml coolant I was trying to figure my options out when I thought where do I get a head fixed out here !?!!! looked it up and there is a guy over in Longreach 215 k away I rang him and discussed my symptoms and he believes my head has a slight warp especially after boiling a few times its only $80 to true the head up again and $25 a valve if needed doing ...... but getting the head off .................................!
Ok so I looked on rockauto gaskets and new head bolts under a $100 posted here I don't think there is anything wrong with my valves so say another $100 for the headjob and probably 2 hrs to pull it off and 2 hrs to refit everything so that about $400 at the mechanics and a trip to Longreach in the PT
$650ish I think should do the trick
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[jaffazoom]

I don't think you have proved anything yet as to what the problem is.

Why didn't you pull the other plugs, if a cylinder is burning coolant you should see a colour difference on the plug. Why only plug 3 and 4 isn't it only the 330 heads on the late model xj's that cracked at 3 & 4.
Doesn't sound like your losing enough coolant.

What about leaving it sit overnight and pulling all the plugs and cranking it over to see if anything gets sprayed out the plug holes.

Try doing a compression check see if any differences.

I hate spending money when I don't have to, be a shame to spend $650 and all that time and still not to fix the problem.

[LuluBelle]

good idea jaffazoom I picked 3 and 4 as they were the easiest mine has extra plumbing for the lpg converter I still think its off with its head I have really boiled it bad in the past but I have to get gaskets and save up for that one in the mean time I will still look at it more
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[awg]

I been following this thread cause my coolant dissapears from the res tank at the rate of ~1litre per 2000km.

It does not seem to be leaking out anywhere.

am going to make a home made cooling system pressure kit,
have a UV torch that shows up green coolant, so when i get time to take the abused DD off the road, will have to check it out

in the past, with head gaskets, there has always been a characteristic poor idle...with associated radiator bubbling and milky oil soon after...never had one "stay the same"..or get better

If I was as suspicious as you, I would be tempted to chuck in a bottle of Chemiweld, which can hold a minor crack or leak for ages

there would be little to lose