XG Overheating

[Shackles 3]

G'day all, 
I know this topic has being THOROUGHLY gone through, but i was hoping to get some insight into whats happening with the old girl. I am out west at the moment so not too much access to a decent radiator place. The XG has being getting hot with summer coming on and the other day went all the way to the red (At midday, shut it down) so have gotten a bit concerned. Has being running warm i guess, but as most of my driving is shortish distances or at night along the highway has never being that hot. It doesn't seem to get hot around town and the viscous fan still kicks in, but take it to 80-100 and it does not like that. As it's a new acquisition when i first got it i put some radiator cleaner through it when i replaced all the hoses and got a lot of black muck out of it - a few more rinses with tap water seemed to run clear before replacing with coolant. I have also noticed the coolant low sensor coming on but that happens sporadically and coolant is always good.

So since it got very hot I replaced the thermostat with a 91 degree high flow unit from tridon, and replaced the radiator cap with a 135kpa non-recovery type (which nearly popped the hoses off so back to original, although sensor light did not come one with the replacment) - This has not made a difference. I lost coolant replacing thermostat obviously so topped it up the next day to halfway between mid and level - when taking it for a test highway driving i pulled over and the coolant had gone above the max on the reservoir and was pulsing around - so i guess the water pump is working. When motor was switched off the coolant settled again.

Their is also no milky consistency to the oil. 

Does this sound like a blocked radiator to you? Any way of checking this, or is their a good replacement option available? Maybe an air lock? although i did let idle with the cap off for twenty after i did the thermostat. Do have a replacement water pump handy but don't want to replace that until i get back home, unless it is absolutely necessary

Cheers fellas

[Mr Polson 10,214]

Was motor/ute flat when bleeding air out? Should be to help air travel through the system I believe.

 

Do the hoses on these have metal springs in them? Taking them out can cause the hoses to collapse/suction in on themselves which can lead to high running temps.

[deankxf 20,264]

you can sometimes feel if a radiator has blockages by tfeel(feels cooler in spots) will need to do this with engine off after running.
check its not full of dirt in the cooling fins in either the radiator or air con condenser, and maybe pull the radiator back and check its not full of grass between the 2(i have seen this once before, not fully, but a good 20% of the way )

check the air bleed hoses arent blocked that run to the reservior from thermostat and radiator(might be blocked at those points also)
OHC dont like air pockets or running without pressure(at least you have mentioned the cap,)

[SPArKy_Dave 8,863]

Sounds just like a head gasket to me, unfortunately.

 

Had that very thing, and those very symptoms happen to me twice, both with XG's funnily enough.

One was due to substandard materials being used.

 

The other time, was due to dodgy workmanship when replacing a head gasket

- a soft cylinder head, from previously overheating.

 

The fire rings and gasket material, often corrode away, between the water passages and cylinders at no.1 and no.6.

[revhead 1,392]

a head gasket on an xg, xh e series donk easy as ,ive done hundreds , just make sure you get it surface ground and tanked to clean it all up an check it for cracks ,most of these alloy heads rott around the rear water galleriers ,but as youve stated its got milk ,il bett its blown into the timing chain gallery at the front an between 1 and 2 cylinders ,most good engine builders will charge you $60 bucks to tank it and $60 for a surface grind, the head gasket set will cost between $90 to $110, stay away from super cheap and repco brand sets as there shitty ,i go for monotorque or similar and remember to got the 30nm and the 90% turn, and yes replace the head studs, 

[revhead 1,392]

also when you pull the head off ,you dont have to take the intake manifold completely off just undo the bolts holding it to the head and leave it sitting roght were it is as it has brackets supporting it ,same with the exhaust manifold undo all the bolts and simply lift the head straight up and out between both manifolds, also make sure you put sealant on the bolts that hold the power steering pump bracket to the front of the head as this will cause you oil leaks after ass, dont forget to undo the chain guide bolt on the very front of the head ,and yes have the motor on top dead centre .also leave the cam on the head as well,use cable tires to hold the timing chain onto the cam gear and undo the bolt holding this on an simply sit it to the side ,cheers ,

 

if you need and more info or hints please ask,

[bear351c 10,269]

You have a recovery tank, but, bought a NON recovery cap??  No way for coolant to get back into radiator.

 

Run engine with the cap off the radiator, if you see bubbles down the hole, it's your head gasket....sorry.

 

Change rad cap, check ignition timing.  A radiator may be 50% blocked and still have clear fluid coming out with a backflush, maybe try a secondhand rad, when you find a wreckers.

 

Let us know how ya get on, matey.

[Mr Polson 10,214]

OP does state he refitted the original cap. Which, may be worth getting an OEM replacement cap and trying that.

 

Also, he does say the oil does NOT have milky consistency.

[Banno 479]

You have a recovery tank, but, bought a NON recovery cap??  No way for coolant to get back into radiator.

 

 

They dont work that way with this type of cooling system. Pull the radiator out and get it flushed and checked, They are notorious for crap between the rad and air con. Sounds like a head gasket leaking out through the exhaust manifold. As revhead said they are easy to replace. 

[Banno 479]

When refill the coolant did you take out the bleeder in the thermostat cover to expel the air. Its an allen key screw into the housing. This proper way to fill coolant in these engines and expel all the air otherwise it will trap air.

[Outback Jack 6,352]

I have never done that Banno. Never had a problem. Is why you put ya heaters on when ya fill up ya coolant and give it a few revs.

Jack.

[Shackles 3]

Thanks for the replies fellas! Gee you all gave me some options to think about.  I tried rebleeding it this arvo on flat ground without the radiator cap (thanks for confirming Mr Polson and outback Jack). After checking air bleed hoses, cheers dean kdc. When idling the level on the recovery tank did come up, and came up even further when revving more. I noticed some big bubbles initially (hopefully air lock), but when giving it a few revs also noticed more of an off white foam – im guessing this is what you were talking about bear351c?. This foam though did settle while running the car. Level decreased after turing off car and letting sit for a while. Thermostat definitely opened. No white smoke out of exhaust though.

So I’m guessing that’s a leak between the coolant and exhaust manifold like Dave said? Thanks for the run through ReVhEad, will be a good excuse to put the the tickford head I have floating around. I heard the go was putting in au mps type gasket – so I will try that I reckon

The only other thing is that part of the gas system sits quiet high, part of it in line with the recovery tank – would their be any point in future in bleeding it with the drivers side front pointing slightly towards the ground? Ill keep an eye for all that crap thanks Banno.

Thanks again lads

[Mr Polson 10,214]

If you do have to replace the head gasket, you can now buy E series kits with the MLS gasket and the correct gaskets to suit the different E series intakes.

You will also have to replace the head bolts, and need a rotational/degree torque wrench.

[Shackles 3]

Just for anyone that is trying that has similar issues in the future. Had a very helpful mechanic give it a good clean, which helped a lot - but the temp would still sneak up. Anyway, when i got back to home i bought a replacement radiator and put that in. Absolute world of difference, never over heats now. 
Cheers for everyone's help!

[deankxf 20,264]

what radiator did you get..

[Shackles 3]

Ahh one from a local radiator dealer here in NQ who deals nat-rad units. Has a 3 year warranty as long as I keep the fluid changes up to it. Doesn't seem like a bad unit

[bear351c 10,269]

Cool.  I've used natrad stuff, never had an issue...