Td5 - 110 - 2005 losing coolant

[applemac]

Hi all

The vehicle:
Defender tD5
Year 2005
Milage 154 000

ECU Mapped - Autologic
Turbo slightly open but not exceeding 20 PSI (Turbo pressure gauge in dash)
Performance intercooler
Engine never overheated


The problem:
It's been loosing coolant for quite a long time at a rate of about 500ml per 1000km.

Mechanic pressure tested it about a month ago and couldn't find a leak.
The vehicle has plenty of power.
Engine oil looks normal, no signs of coolant. (no mayonnaise)

It's now at the mechanic to do other stuff (Clutch) and will be pressure tested once again, this time overnight.

I also asked to remove the EGR and cooler and bypass the coolant hoses to the heater. I was told that these two items could be the source of the loss of coolant.
The EGR system was blocked at the exhaust manifold side anyway.

I'm also told that it's very unlikely to be the head gasket (????) with this engine, considering the milage and it has never been towing or overheated.

Question ?

Does anyone have any suggestions or had a similar problem ?

Obviously tomorrow's diagnose after being left overnight pressure testing could shed some light, but since it didn't in the past I wonder if anyone in the community has some ideas.

Thanks in advance

[slug_burner]

Pressure cap on cooling system?

[jimr1]

G'day mate , try looking on the right under the engine shroud , at the little bypass hose , mine was leaking there , took a while to find It . Like you couldn't find were the coolant was going . Another tip , that plastic hose that runs from the radiator to the expansion tank goes brittle , and will crack without any warning , mine went , and I have also heard of others , check under the cover over the radiator , see if It's flexible , be careful It may snap !!..

[jimr1]

One other point I meant to ask is let us know if you find out what coursing you problem , cheers Jim ..

[applemac]

Pressure cap on cooling system?

Pressure cap was replaced awhile ago to remove that possibility.

[applemac]

One other point I meant to ask is let us know if you find out what coursing you problem , cheers Jim ..

Will do.

I'm hopeful we'll find a leak by tomorrow and even more hopeful that doesn't end up being a cracked head or something else engine related.

I did have a similar problem with a Nissan Patrol 2.8 a few years ago and ended up being a cracked head. The crack fortunately being near the exhaust manifold and so the coolant was going out through the exhaust system. In that case the engine oil showed signs of water (coolant) contamination, a thicker oil paste forming in the engine cap, it was a new head, an expensive job.

[applemac]

We found the leak.
After leaving it overnight pressure testing it didn't show any leaks but, it was then pressure tested running the engine hot and we finally found it.

It was a screw on the top right side of the radiator. Unfortunately sealant won't do the job and the all unit has to be replaced.

Luckly the mechanic next door had a second hand one from a Puma circa 2009 that is in good conditions and cheap. Someone did un upgrade to their Puma and there is nothing wrong with the original radiator.
See picture.
79175
Hopefully this will be the end of it.

Thanks to everyone

[rangietragic]

G'day mate , try looking on the right under the engine shroud , at the little bypass hose , mine was leaking there , took a while to find It . Like you couldn't find were the coolant was going . Another tip , that plastic hose that runs from the radiator to the expansion tank goes brittle , and will crack without any warning , mine went , and I have also heard of others , check under the cover over the radiator , see if It's flexible , be careful It may snap !!..

Mine was doing same thing,was where small hose joined heater on engine block.Fitting was corroded away.