PROBABLY the most annoying problem in the world...

Hi m8, when you changes the thermostat did you get an after market one or OEM makes a big difference, after market ones will work intermittently sometimes working fine and then not working, I would stay at not much cost, take it out and run it without and see what its like if (dont forget to put it back again) just to test its that or not first

Drop it in hot water to make sure its opening and closing as well, but buy an OEM

Check you have no air in the system

(do the things that cost you no ££ first)

You can get cheaper thermostats, made from the same company that make them for Land Rover at about £15

Cheers, It was (apparantly) Genuine part, as for the air, I THOUGHT is bled it all out but when i went to bleed again water just started pouring from header as soon as normal temp was reached. Had wondered, for all they cost, if i should just get another stat?

I would wait till you get a few more responses first, then decide, did you put any antifreeze in?

Then look at your water pump, and the belt tensioner (like a little nematic arm)

test thermostat using a thermometer put in pan of cold water heat it up on the cooker and see what temp it starts to open and when it is fully open.
the temp is stamped on the stat and should be fully open when it reaches that temp.
i have had a britpart stat cost me an engine and a gen landrover one which opens at the wrong temp.
most likely is a cracked head get it sniff tested for combustion gasses in the coolant.

I'm really hoping it a dodgy stat. Will test at the weekend. No nasty smell in the header, clean oil and coolant. I did have about 50 miles between today and previous incident.

Could well be a duff RAD, check it gets hot all over. There is a baffle in the centre of the top header that fails and when it does the water just goes straight across the top of the RAD instead of down one side and up the other. The water pumps fail too, the impellers are plastic and tha vanes drop off. Don't keep overheating it because if the head is not already cracked, it soon will be.

Datatek said:

Could well be a duff RAD, check it gets hot all over. There is a baffle in the centre of the top header that fails and when it does the water just goes straight across the top of the RAD instead of down one side and up the other. The water pumps fail too, the impellers are plastic and tha vanes drop off. Don't keep overheating it because if the head is not already cracked, it soon will be.

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is it best to approach radiator from the front with the grill off?? I figured the pump was ok - gave it a good rev with the cap off and water rushed out.Also I'm sure ive seen a bit of paper showing a new one within the last couple of years. Ive been pretty careful to kill it before it gets too hot - ive got used to the warning signs!!

You can feel some of it from underneath, all of it if no aircon. I have a 96 that was diagnosed with a cracked head, the RAD was fecked, it may or may not have a cracked head, but with no cooling it was bound to overheat.

im sorry to say if the water is being pushed out of the header tank sounds like headgasket to me if water pump was not working it would not push water up to top hose try testing when cold if radiator a quick test is to take it out if it feels light in weight when emty thats a good sign if heavy im afraid its blocked when i changed mine due to over heating i found the old radiator was four times heavier than the new one but i did not have water pushing it self out the header tank usually pressurised due to head gasket hope this helps

With the pressure cap removed, it's possible for the coolant to boil which will push it out of the filler cap. A duff filler cap not holding pressure will cause the same problem. The cap can be very tight to screw all the way down, if it's not down it will not hold pressure and the coolant will boil.

I agree with all of the above, take the cooling system apart and check the parts don't rely on what the previous owner has told you.

As you say 750.00 is a bargain for a good V8 Rangie with an MOT, let alone a diesel.

I'd be inclined to get the cooling system pressure tested to check the head/gasket and then if ok replace the remaining cooling system.

I understand that some replacement water pumps have metal impellers, so I'd check before buying.

thats why you are supposed to take the cap off slowley thus preventing any build up of normal pressure to not spray out everywhere once the cap is off pressure released ....if water starts to overflow then ....pressure from head gasket is building up

Thanks for all the advice... I think my next plan has to be strip out and test stat, check pump, take out and check radiator etc etc bleed, and cross everything!!
There are a couple of shiny new bits below the tensioner (possibly pump?) but no harm in checking the whole lot. Anyway the wife loves it when I need to spend hours tinkering.
I have to say, if all else fails and the head is knacked, I'll probably replace (after a few homers). It is a cracking big truck I'd like to get to use it!
Will get my hands dirty this weekend and keep you posted!
Cheers,
DB

Sounds odd, but has anyone considered that this might be a straightforward coolant leak, maybe only manifesting itself under pressure? Reason I mention this is the description of the heater suddenly getting cold before the overheating starts. I've seen a similar issue (on another make) which turned out to be a dodgy rad cap - not enough spring pressure to keep closed under pressure which led to coolant loss and similar symptoms as described. Or perhaps even a hose letting some coolant go under pressure.

As Datatek said, once you take the cap off with hot coolant, you release the pressure that keeps it liquid and it will boil up and overflow. This would happen on a perfectly health engine, so don't necessarily consider this a symptom of your fault.

Re: PROBABLY the most annoying problem in the world...

Why is it when you've had a sloppy poo yer fingers go through the tissue.

Why is it when yer busting for a fart at a party, every ****er goes quiet.

Why is it when yer busting fer a **** the ****er won't let go.

Just wondering like

thing is how many dse owners have gone through replacing the entire cooling system radiator thermostat waterpump, viscous etc etc spending a fortune never curing it till the head is removed and low and behold the head is cracked!
get it sniff tested for combustion gases in the coolant before wasting time and money on anything else. cheapest and most simple thing to do first!

6704nathan said:

thing is how many dse owners have gone through replacing the entire cooling system radiator thermostat waterpump, viscous etc etc spending a fortune never curing it till the head is removed and low and behold the head is cracked!
get it sniff tested for combustion gases in the coolant before wasting time and money on anything else. cheapest and most simple thing to do first!

Click to expand...

Quite right, but if the head is cracked, it was probably caused by an overheating problem in the first place, so a complete overhaul of the cooling system is not wasted and indeed should always be done if the head is being replaced.