Losing coolant 05 TDV6 S

[talltales]

This is a strange one. I had the water outlet assembly blow apart while towing my camper up a rather large hill. Water shot over the whole engine. I shut down and was fortunate enough to be able to replace the unit without moving. Since then I have been loosing 1-2 ltrs of coolant every 400kms without any heating issues. I and my mechanic and about three others cannot find where the coolant is going as there is none in the oil and no oil in the coolant.
Has any one else had this issue?
Car is still running fine. We have found some coolant marks at the back of the V block onto the gearbox bell housing but am yet to find a definite leak.
We have pressure tested to 110kpa and had it drop to 100kpa and hold overnight with no water leaks present. Once I run the car hot while driving the coolant level drops.
Any assistance would be appreciated.

[connock]

Hi talltales
Have you looked very carfully in the front of engine V. Mine was leeking small amounts from the Y junction in water gizmoe front , easy fix but was hard to find. I could take a pic and send it to you if that would help ?
connock

[tomisawesome]

have you pressure tested the cooling system while the engine is at operating temperature?

[talltales]

Hello cannock. A photo would be great thanks.
Tom we ran a quick pressure test while hot yesterday and still held 100psi after an hour. We are going to do more testing today.
Thanks for the replies.

[400HPONGAS]

100 psi ??? WTF ? How many pieces is your radiator in now !!!!You wouldnt have a hose left on it of the 32 minor and major hoses fitted to a TDV6. Probably meant a 100 Kpa .(and that was a "quick" pressure test !!)

[pohm66]

Also check the thermostat coupling, ironically it doesn't house the thermostat.....

I had a slow leak that couldn't be found until it blew :( luckily 10ks from LR mechainic

The coupling it made of 2 plastic pieces that are sonic welded and this is what fails.

Cost for part $40 BUT needed to import from USA

[connock]

Hi talltales
If you remove the Y junction (air inlet) and have a look at the water housing under it, this is a plastic fitting and is subject to splitting. Taking Y junction off is about 5mins
connock

[talltales]

Thanks for the photo Connock. That was where the problem started and I have had that replaced and rechecked and all is okay, It seems that I am burning the coolant through a blown head gasket. I am in the process of assessing costs and keep you informed.
Also have a look at the Blown head gasket thread.