I drove 200 km yesterday, no leak from the cap. Checked coolant level this morning and it is still the same! Also there's no more leak from the quick coupling. Yesterday morning it was literally dripping. There is still some moisture on the under tray and coupl8ng which clearly shows there indeed was a coolant leak at some point. How can this just come and go??
I'm replacing both the hose and the cap on Monday anyway...I'm doing many thousand kilometers in this car so I'm not taking any chances.

One thing I've noticed and can't just ignore: This car is mostly leaking when it's not driven for a while...go figure...

Probably hairline cracks then if it leaks when not driving. I had that on mine. Was chasing it for a while. I could drive hundreds of miles with a warm engine. But let it cool off and stand for a few days and I found the level dropped significantly. Simply a case of changing those hoses as they do need replacing over time.

The cooling system is notorious for air locks, it could be you had one that has now worked it's way out, whilst there it increases the pressure in the system and it will leak at the cap... When it's gone the leak goes... Worth changing the leaking hose and then bleed the system through well, check all hoses are warm when it's at running temp... some will be cooler than others but none should be cold...

p38arover A basic OBD diagnostic tool should tell you if the system is running closed loop...  Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Thank you gentlemen for the valuable advice. It seems as if the leakage of the water pump was acting as a relief and now the weakest spot has been exposed in that hose's quick coupling. I'm wondering if air could be drawn into the system from a hairline crack or a failing coupling. Then cause an air lock and a leak from the cap.
Will get the work done on Monday and report back. Oh and I'm really looking forward to finally fitting those new air struts

And as I’m sure you know. Once you’ve fixed the next weakest point, the following one will rear it’s ugly head. My attitude is that if one goes then it won’t be long before others go. Hoses are cheap, my time or labour of others isn’t. In my opinion it’s best to change the lot and then have another 10-15 years of trouble free cooling system.

Haylands wrote:

p38arover A basic OBD diagnostic tool should tell you if the system is running closed loop...

! I don't have a basic OBD tool.

I've only got a T4, a Faultmate MSV, and a GAP IID Tool (and access to Autologic)!

I'm not sure where but I'll have a look. Ron B. VK2OTC
2003 L322 V8 Auto
2007 Yamaha XJR1300
Previous: 1983, 1986 RRC; 1995, 1996 P38A; 1995 Disco1; 1984 V8 County 110; Series IIA

IID should have it somewhere...

You should know if it's not closed loop as it will use more fuel... Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Bl4ckD0g wrote:

And as I’m sure you know. Once you’ve fixed the next weakest point, the following one will rear it’s ugly head. My attitude is that if one goes then it won’t be long before others go. Hoses are cheap, my time or labour of others isn’t. In my opinion it’s best to change the lot and then have another 10-15 years of trouble free cooling system.

Judging from what I've faced so far I should have replaced all hoses from the get-go. Most all faults (so far) have been rubber gaskets, o-rings and hoses. At the moment many of them have been renewed.
Some time next year I should be tackling the timing chains and Vanos. I have no problems at the moment, other than a bit of oil sweating through the upper timing chain cover on the left hand side. So small that it won't make any difference in the leven between oil changes. But chain guides are inevitably due to fail at some point.
I will change the entire set of hoses while at it.
I'm slowly gathering the parts and talking my indy into

The bottom part of your rad has a takeoff for the transmission cooler, there is a manifold and separate thermostat down there, the bottoms of the rad sludge up as the bottom hose is high up on the side of the rad so the water in the bottom doesn't move much...

This leads to high transmission temps which will kill your gearbox...

My rad looked perfect from the outside, it was sludged so much it would not clean out even after removal and back flushing...

If I bought another 4.4 I would do the lower temp mod, replace all the hoses, the radiator, the transmission cooler, gearbox thermostat and manifold as well... I did all that on mine over a period of time and it ran so much better after, engine and box felt 10 years younger...

If you are going to keep it then well worth the trouble...  Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Here you go...

Click image to enlarge

Haylands wrote:

The bottom part of your rad has a takeoff for the transmission cooler, there is a manifold and separate thermostat down there, the bottoms of the rad sludge up as the bottom hose is high up on the side of the rad so the water in the bottom doesn't move much...

This leads to high transmission temps which will kill your gearbox...

My rad looked perfect from the outside, it was sludged so much it would not clean out even after removal and back flushing...

If I bought another 4.4 I would do the lower temp mod, replace all the hoses, the radiator, the transmission cooler, gearbox thermostat and manifold as well... I did all that on mine over a period of time and it ran so much better after, engine and box felt 10 years younger...

If you are going to keep it then well worth the trouble...

p38arover wrote:

D3Jon wrote:

LR changed to the higher pressure cap and a different cooling system design on the M62 V8 around 2004. You'd have to supply your VIN number to a LR dealer to obtain the correct cap for your car.
<snip>
Not only did the cap's pressure rating change from 140Kpa to 200Kpa (20psi to 29psi) ,

Unless I can't read MicroCat correctly, that appears to be incorrect.

It appears the 200kPa cap was fitted up to VIN 1A001049 and the 140kPa cap thereafter.

PCD000070 (CAP) [ (V)1A001050 - ]
PCD100200L (CAP) [ - (V)1A001049 ]

I'll have to double check what's on mine, it's one of the very first L322's (2002). I had 'fun and games' getting the correct cap when I worked on the cooling after a hose blew, so I replaced the majority of the hoses as a precaution. No issues since.

I was sure that the later cars run higher pressures, but happy to be corrected.

Ron - I'm sure you're reading MicroCat correctlt, let me just re-assure myself first! I'm going outside now to look

Jon 1992 RR Classic 3.9 efi Vogue
2014 Disco 4 HSE
===================
Both my fatties now gone...
Previous: 2011 L322 4.4 TDV8 Vogue SE /// 2002 L322 4.4 V8 HSE /// 2009 Discovery 3 2.7 TDV6 XS /// 2004 Defender 90 TD5 /// 1993 110 V8 Snatch Landrover /// 2005 Discovery 3 2.7 TDV6 SE (Aus) /// 1990 110 Isuzu 3.9 County (Aus) /// 1976 Series III Trayback (Aus)

Yep, I got it the wrong way around... The earlier cars have the 200 cap - mine has! Doh  1992 RR Classic 3.9 efi Vogue
2014 Disco 4 HSE
===================
Both my fatties now gone...
Previous: 2011 L322 4.4 TDV8 Vogue SE /// 2002 L322 4.4 V8 HSE /// 2009 Discovery 3 2.7 TDV6 XS /// 2004 Defender 90 TD5 /// 1993 110 V8 Snatch Landrover /// 2005 Discovery 3 2.7 TDV6 SE (Aus) /// 1990 110 Isuzu 3.9 County (Aus) /// 1976 Series III Trayback (Aus)

vs322 wrote:

A quick question: I drove about 100Km today again with no coolant leak observed. Upon switching off the engine, I noticed that the expansion tank cap was hissing slightly then soon stopped. No coolant emerged. Is this part of its normal operation?

I never noticed mine doing that, mind you mine was changed to a lower temp so lower pressure as well...

Do the stat mod, or swap, and then see if it does it...  Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Haylands wrote:

IID should have it somewhere...

You should know if it's not closed loop as it will use more fuel...