Afternoon,

I have had a good search around the forum, and other to try and solve my water loss issues, but nothing seems to be on the right track. Sorry if this thread has been up a few times, but it’s doing my head in now.

So here’s the story.

It’s a 2000 TD5 disco with 98k on the clock.

I first noticed the coolant to be low after the heater started to blow cold all the time. So I topped up the reservoir (it took about 4 litres!). This solved the cold air issue, lovely and warm now
But since then, I keep noticing the blower blowing cold air; again go to check reservoir, its near empty, and another 4 litres.

I took her on a run to Scotland and back last week, we did about 1500 miles in her, not a drop of water missing, heaters lovely and warm.

Been driving round Sheffield, a few small runs (about 20 miles or so each day). Heaters blow cold again, reservoir is empty, another 4 litres.

So there’s the issue, I’ve checked the head gasket with a sniff test, checked the hoses, not pressurised, I’ve checked the reservoir cap, I’ve pressure tested her. All good. I’ve had a good look round her, no leaks that I can see, a bit of OAT crust around the top pipe going into the block, and temp sensor, but not damp in any way.

The only symptom a do have, is the noise of running water / trickling coming from the dash when I accelerate. This seems to be hit and miss, it’s not every time, but it is most. The carpets inside are not damp, I’ve had my hand all up and around the dash and console, dry as a bone. So not suspecting the heater matrix.

So...... where is the 4 litres of water going??

Any help would be appreciated.

I’m a mechanic by trade, and it’s a bit embarrassing having a car with a mysterious water leak. But im stumped, and so are the other lads in the workshops around me.

Thanks

header cap has been known to fail, there is a valve inside them

Hi Joe,
If you've ruled out the head gasket there are a couple of other places people have found "mystery leaks".
Core plug under exhaust manifold.
Short rubber hose on oil cooler.
Coolant elbow on n/s of engine under acoustic cover.
The water noise under the dash sounds like the cooling system needs bleeding.
HTH,
Griff

I had a slight leak on the rad - not enough to see anything but general dampness underneath. But it wasn't losing anything like yours. But 4 litres in a few days - can't imagine that much coming from a minor leak.

Thanks for your replies, ive check all the areas you mention landmark2. All seems to be fine.
Johnlad - what are the syptoms when the cap fails? water passing through the cap? if that is the case, this is definitly not happening.

I topped her up last night, went to pick the misses up from work (about 5 miles). then shes not moved since then. Been to check reservoir today, she took 3 litres.

Im going to give her a really good check over tomorrow, and bleed the water system. But it seems to be losing water when stood, rather than driving? there is no wet patch on the floor where she has been parked. Really starting to confuse me now.

thanks

if cap fails it cant release excess pressure so water gets pushed through overflow and comes out at the side of the rad

johnlad said:

if cap fails it cant release excess pressure so water gets pushed through overflow and comes out at the side of the rad

Click to expand...

over flow exits at pipe on side of expansion bottle ,pin hole in rad is common

jamesmartin said:

over flow exits at pipe on side of expansion bottle ,pin hole in rad is common

Click to expand...

yeah the pipe comes out of bottle but is routed to the side of the rad on my td5

Had a leak from mine with nothing coming out underneath. Eventually found that water was leaking from the pump and lying on the muck plate and obviously evaporating. Changed pump and then ok.
Shone a torch down the side of the top hose to see it.

A very weird problem! Have you taken the Disco for a run to get her warmed up, then parked up with the engine running and had a look for steam escaping...anywhere! :O Should be easier to spot with the weather getting cooler.

My sons TD5 had the same symptoms as yours. We swapped header tank caps (I have a D2 as well) and the problem went away.

i had the same problem, was dreading the head gasket! so changed thermostat, new rad and a new expansion bottle cap, been ok ever since, so for £130.00 for the parts was a lot cheaper than the head job