TOTAL MYSTERY Coolant Loss!!!!

dooroy said:

Then I noticed some traces on the cylinder head - there is like a big plug screwed into the side of the head on exhaust manifold side. This apparently was leaking

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Thanks very much for this.....I have asked many times before if anyone knows if there is an external core plug or something similar high up on the engine but nobody has mentioned this so I assumed there wasn't...this could well be the problem cos it would also be the reason it holds pressure cold but not hot; and its is also in a position where large amounts of leaking fluid whilst driving would get evaporated quickly due to the heat and not leave any moisture...cos its always been the real puzzle...WHY CAN'T I SEE SUCH A BIG LEAK??.... I have booked it into my local garage man to do the bottom hose, as i have a busted hand and can't do stuff myself at the moment... I will ask him to investigate...cheers

Good luck, I am watching this thread with interest as I reckon I am in the same boat.

DaveJ said:

Good luck, I am watching this thread with interest as I reckon I am in the same boat.

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OK Dave...it isn't going to the garage until Friday so will get back with an update in a week; I am getting them to have a look for possible external leaks including this plug in the head whilst they are under the bonnet - so here'e hoping we find it

Mike

DaveJ said:

Good luck, I am watching this thread with interest as I reckon I am in the same boat.

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I forgot to add.....don't lose sight of the fact that, until this bottom hose started to leak, the low level never gave me a problem except it did eventually need a bit more put in as the heater would stop....once the hose is fixed, at worse, i hope to back in a stable, though abnormal, situation again.....if yours is low but steady, maybe you will be able to pretty much ignore it too

Hi there, my discovery td5 loses coolant if it is topped up to the correct level and if you drive it hard it sends the coolant out of the overflow pipe until it is low in the headertank then it stays there at a low level and everything is fine.but it shouldnt do that and after many different tests i suspect the head gasget is leaking combustion slightly and forcing water out.fill your coolant up to the correct level blast your landy and see if any water is coming out of the overflow pipe.

I would be of the opinion that if the head gasket was leaking the coolant loss would continue to the point of emptying the system - same would apply to leaks ; when the engine is warmed up and pressurised coolant will be pushed out whether the leak is high up or low down ;
When the coolant is topped up to its normal level there is some expansion level left at the top - if you fill up to the very top the extra will be forced out when the engine reaches normal temp .
I feel that some engines need more 'expansion' space in the bottle - and will force out coolant until this space is available. If you could monitor the system at the lower level you may find it performs as normal - just that the level is at a much lower level when cold .
I came across a similar problem with oil levels in some engines - fill them to the max and within a short time they would be half way between max and min . But they would stay at that level for weeks then - the dipstick marks are an average and some engines seem to choose their own level .
This is only an opinion - but have seen this on a number of engines which did not have a failed or failing HG .

dickie dave said:

i suspect the head gasget is leaking combustion slightly and forcing water out.fill your coolant up to the correct level blast your landy and see if any water is coming out of the overflow pipe.

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Thanks but its not the head gasket; all gas tests have come up clear. And the coolant is definitely not coming out of the overflow - i extended the overflow into the cab with a vented bottle on the end to check that whilst I was running....still had the same initial coolant loss

dooroy said:

I would be of the opinion that if the head gasket was leaking the coolant loss would continue to the point of emptying the system - same would apply to leaks ; when the engine is warmed up and pressurised coolant will be pushed out whether the leak is high up or low down ;

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Yes I agree with your head gasket comment; it would also produce an overpressure and the system is,if anything, rather low on pressure.
I think a high up leak could stabilise though because I have run the engine from cold at this very low water level without the air bleed screw in and in this situation, with no system pressure that hose runs almost empty, so a leak this high up does allow you to run without losing fluid (though I suspect under load when the pump is really producing pressure you may be right and coolant would still get out)

Its in the garage as I speak so here'shoping they find something

easiest way would have been to simply fill coolant level to top of expansio0n bottle and have a leakdown test done on it..

This is simply a hand pump and pressure gauge that fastens to rad or expansion bottle and is pumped up to pressurise the system. then the car is inspected for obvious leaks whilst under pressure if none is found the car is then left over night to see if the pressure holds.

redhand said:

easiest way would have been to simply fill coolant level to top of expansio0n bottle and have a leakdown test done on it..

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That is what they have done in the garage. It went in yesterday morning and they fixed a tiny seeping leak on the pump outlet, exposed all the coolant pipework so they could see the joints then did the leakdown test.....NOTHING VISIBLE...they left it at pressure all today and it was still over 90% of original pressure after 24 hrs....so no leaks
I have the car back now and can see nowhere to go from here... I know as soon as I start driving it the coolant will be down the bottom of the tank the next time I stop, followed soon after by no heating - not much fun when its 10 below!!!!.......looks like its another punter changing to japanese.....bye, bye landrover

you do know that coolant level in a disco is the seam on the expansion bottle. Don't you??

redhand said:

you do know that coolant level in a disco is the seam on the expansion bottle. Don't you??

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Yes, I do...I SHOULD BE SO LUCKY!!!!!!!!!!........my "stable" coolant level when cold is a barely visible 1cm above the bottom of the tank...when its hot it often disappears...!

I am not going to throw any more money at it unless I can come up with something that explains where the fluid is going....everything obvious, and the less obvious have been suggested and tried....

redhand said:

you do know that coolant level in a disco is the seam on the expansion bottle. Don't you??

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That's not quite accurate for a TD5 engine. The correct cold-engine level mark is on the engine side of the header tank and is approx 2cm below the seam.

thebiglad said:

That's not quite accurate for a TD5 engine. The correct cold-engine level mark is on the engine side of the header tank and is approx 2cm below the seam.

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AHHH!! Thanks for that...at least that's a bit closer to where mine is

I had noticed that if you fill with the bleed screw off, it comes out of the bleed hole before it reaches the mark on the seam.....Why is the arrow moulded into the header tank on the seam line?

I am doing a long trip tomorrow to give it a proper test since its come out of the garage.....so will post whether its any better...if its not I will sign off the thread and just remain perpetually puzzled

As a matter of interest, how much fluctuation in the header tank level do peeps get on their D2 TD5's between fully hot and stone cold?????

My peugeot 307 HDi doesn't fluctuate at all over its whole temperature range

Manicinfrance said:

AHHH!! Thanks for that...at least that's a bit closer to where mine is

I had noticed that if you fill with the bleed screw off, it comes out of the bleed hole before it reaches the mark on the seam.....Why is the arrow moulded into the header tank on the seam line?

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On mine the header tank level mark is as I said on the engine side and approx 1-2cm lower than the seam. Can't remember about the arrow to be honest.

That level stays constant on mine irrespective of usage and conditions.

thebiglad said:

On mine the header tank level mark is as I said on the engine side and approx 1-2cm lower than the seam. Can't remember about the arrow to be honest.

That level stays constant on mine irrespective of usage and conditions.

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Maybe you have a different header tank to mine...but the actual level mark isn't that crucial, wherever you fill it too it ought to stay there.

If I fill mine to the line cold, it drops about 2-3cm when hot then comes back up when cold (except of course mine is operating like that right at the bottom of the tank.......

I am going to blaspheme now.........

I am on ebay looking at Toyota Landcruisers
:alien:

death to the unbeliever!

Thought I ought to update and thank all for your comments as nothing new will arise now.......I have given up....if anyone stumbles on this thread in the future and can solve the mystery I would be most grateful...:amen: