Coolant Loss

Hi, having an issue with losing coolant but do not have a clue where it is leaking from. My Disco is a 2000 TD5. I seem to be losing like half a litre every couple hundred miles. I got no oil in water, no water in oil. No overheating, gauge stays in the middle. No obvious leaks from what i can see. The header tank cap hisses when released after a run so pressure is there. Although have noticed that the top hose always seems to be soft whether cold or hot. Not sure if this is normal or not?
If anyone could shed some light on the subject that would be great.
Thanks

Mine had a leak from the water pump which lost a similar amount. If you lie underneath you might be able to see it dripping off the side of the engine.

Although the pump on mine was replaced and the leak stopped about 6 months ago it now seems to be losing a small amount again......

I will get underneath and have a look although i am not getting any puddles under the car.
Thanks for reply

Im concerned it may be head gasket but just wondered if anyone else had similar problems that may be worth me checking first???
Thanks

I notice from your signature that you have removed your EGR. I was going to suggest checking the EGR coolant pipe that runs from the header tank to the EGR cooler (if you have that version fitted). Mine rubbed,split and left me with the same symptoms as you.

It might be an airlock somewhere pushing coolant out of the header cap. Run the engine with the cap off for a bit or unscrew the bleed nut on the top of the main coolant hose going into the rad.

Had the same problem - pressure test on the radiator revealed a very small leak

I had a coolant leak on my 2001 GS TD5. I traced it to a very slight weep from behind the flanged plate on the back of the water pump. LR do a service kit (3 off 'O' rings) that cured the problem. ( I wonder how many owners erronously replace the complete water pump due to this?).
I also cleaned the header tank out with bleach and M6 stainless steel nuts (the nuts to remove the crud from all the nooks and crannies inside the tank - make sure they all comeout!). I refilled with new G12 coolant and all seemed well. I noticed after a couple hundred k's that the level went down by about 300ml. I put this down to the air being purged from the sytem and topped up. The same thing happened again. I topped up. The same thing happend again.....so I left it. The level didn't go down any further, but is 13 mm lower than the mark on the tank. 4000 km later the level it still were it was - 13mm lower than the mark on the tank.
Hope this helps.

Have the same problem on mine. Deffo not the head as I had it tested two weeks ago and it was all clear but continue to lose water.

No obvious leaks or anything and no puddles or anything.

Saying that mine leaks oil and power steering fluid so not sure I would notice LOL.

also concerned its head gasket, we were losing coolant, no overheating, was head gasket.. is the bleeder valve done up tight on the top hose??

Is there a split in any of the hoses? somtimes they split at the end if the clamps are done too tight...

Ok thankyou very much everyone for all your input and help, i am going to check all these areas out but wont be till weekend now. When i fitted my DE-EGR kit i removed the top hose from engine and found that it had been leaking where it connects to engine ( rubbish spring clips) So thought this was the source of the leak. Re fitted with Jubilee clips and now pipe doesn't leak. So hopefully its just air locked. Also been told by local Landy specialist that could be Header tank pressure cap passing so am also going to rig up a bottle on end of overflow pipe just to check this.
Will report any findings.

Thanks again guys!

sometimes the area where it connects to the engine can do with rubbing down a bit.. my hose split in that exact same place, also lost some coolent there before i changed the clamp

Yeah i had to rub down the little unit the pipe fits on before refitting else probably wouldnt have re sealed.
Thanks

Now i.m having a bit of a strange one. Anyway for now i have ran it up to temp and bled the air out of system, not much air in there but a bit. Have fitted a bottle on the end of oveflow to check if header tank cap is passing so will check again tomorrow.
Now the strange thing. i was sat in the car just revving it up to get it up to temp and i could hear what seems like running water. Now obviously i know the heater matrix has got water running through it but should you be able to hear it? As you rev it up it appears to get louder and faster. I do not have wet carpets so will rule out it leaking for now.
As its now dark i gave up messing so may get chance to look tomorrow again!

Had a good look today and found nothing! Anyway enough is enough, its going in next week to my local Landy specialist and see what they can find!
Thanks

TD5mm said:

Now i.m having a bit of a strange one. Anyway for now i have ran it up to temp and bled the air out of system, not much air in there but a bit. Have fitted a bottle on the end of oveflow to check if header tank cap is passing so will check again tomorrow.
Now the strange thing. i was sat in the car just revving it up to get it up to temp and i could hear what seems like running water. Now obviously i know the heater matrix has got water running through it but should you be able to hear it? As you rev it up it appears to get louder and faster. I do not have wet carpets so will rule out it leaking for now.
As its now dark i gave up messing so may get chance to look tomorrow again!

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The sound of running water is often a sign of HG. My 1999 110 TD5 had a headgasket gone when I bought it. It didn't overheat on me but would overpressurize. Do the hoses on yours go solid after a run?

I wouldnt say solid but are definately harder to squeeze. If it over pressurizes though shouldnt it empty the water out through the pressure cap and out the overflow? If so mine is definately not doing that. Did you do HG yourself or pay someone? if so how much did it cost? Im not that concerned about HG really but if its going to cost me a fortune then i will be lol. thanks for reply

So should the hoses go solid after a good run? They are always soft when cold so no build up of pressure when cold!

Thanks

TD5mm said:

I wouldnt say solid but are definately harder to squeeze. If it over pressurizes though shouldnt it empty the water out through the pressure cap and out the overflow? If so mine is definately not doing that. Did you do HG yourself or pay someone? if so how much did it cost? Im not that concerned about HG really but if its going to cost me a fortune then i will be lol. thanks for reply

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It all depends. It could empty the gas pressure rather than the coolant.

I paid someone to do mine as I knew there could be a problem with getting the head skimmed. My theory was it saves argueing over who's fault it was if it failed if the engineer that was skimming and pressure testing it did the whole job from start to finish. I'm glad that I did. My landy still wasn't right so I took it back after 6 months and insisted he take the head back off. It turned out it was cracked in 2 places and it hadn't shown up on the original pressure test. It originally cost me £500 all in. It then cost me another £300 for a replacement head.

TD5mm said:

So should the hoses go solid after a good run? They are always soft when cold so no build up of pressure when cold!

Thanks

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They should be firm but not rock hard after a run. Mine would run on tickover with no problems. I could leave it running all day with no issues. Give it a 5 min run and the hoses were pressurised to the point that I couldn't squeeze them flat. If you have a cracked head or HG gone you would lose the pressure through said fault when stood up so I wouldn't expect it to be pressurised.

I had a small leak from my 2001 Td5 - after much searching tracked it down to top corner of radiator ; only visible sfter cowling etc had been removed. And if the leak is small the water will evaporate so no puddles !!!
As regards pressure in the system I found that while all vehicles pressurised the system when hot the hoses etc went soft again as the engine cooled down .
If the head gasket was leaking I often found that the pressure remained in the system - even with the engine cold .
So in your case if the hoses are soft when cold its unlikely (but I stress unlikely )to be head gasket.
Have been meaning to get one of those kits which can test the coolant for traces of hydrocarbons - put an end to the guesswork .

dooroy said:

I had a small leak from my 2001 Td5 - after much searching tracked it down to top corner of radiator ; only visible sfter cowling etc had been removed. And if the leak is small the water will evaporate so no puddles !!!
As regards pressure in the system I found that while all vehicles pressurised the system when hot the hoses etc went soft again as the engine cooled down .
If the head gasket was leaking I often found that the pressure remained in the system - even with the engine cold .
So in your case if the hoses are soft when cold its unlikely (but I stress unlikely )to be head gasket.
Have been meaning to get one of those kits which can test the coolant for traces of hydrocarbons - put an end to the guesswork .

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It depends on how it fails and how long it's stood up for too.

The sniff tests won't always show up a HG problem. My landy passed 3 sniff and 3 compression tests plus the compression test when it was skimmed. My head actually had 2 cracks in it.

I actually covered 3000 miles with the cracked head and it drove fine except for the overpressurising.