Loosing Coolant

Can someone help me please with a bit of advice?
I noticed recently that my Discovery 2, TD5, has lost some coolant: about 100mL over about 60 miles since I did my last weekly checks. I've had the car about eight months and it has always been fine, having done ca. 4000 miles including six long (500 mile) trips - the coolant dial always being stable at half-way and the coolant levels in the filler tank being stable also.
Checking the engine there is coolant staining near the upper hose where it joins the engine and on the under side of this hose section (as picture):
The above is by far the most evidence of leaking coolant, and I have never noticed it before. There is also evidence of coolant trickling down the vertical section of this hose further to the near side where it branches downwards from the T-junction. And there is also some minor coolant marks near where the hose enters the radiator though I am not sure if this is old (picture attached - though not very clear):

There is no 'mayonnaise' in the oil filler cap and the engine drives perfectly.
What is the best thing to do in this case? Is it a matter of trial and error by first taking the hose off and replacing it to see if that cures the problem? Or is there any other way to check whether this could be more serious (i.e. head gasket of cylinder head). Or am I reading too much into this? I'm trying to avoid spending money on a new upper hose assembly if it is something more serious?
Thanks for any advice?
Andrew

Is that brown clip for the temp sensor? Looks like it's leaking

A quick note, may save you a headache.

Be very careful of the small diameter radiator hose connection on the rad itself, people have been known to snap them off and that means a new rad.

Also the small hard plastic pipe that connects into this conection, be careful with this as well as they get very brittle and will snap into pieces a the slightest provocation.

Good luck finding the leak. Whilst you are looking for it, also check the oil cooler rubber pipe under the turbo as they have a habit of cracking where the rubber connection is to the metal pipe that runs around the back of the engine ( some later engines do not have the connection pipe and have a blank on the oil cooler outlet).

Cheers

Thanks for the prompt replies and the information.
That brown clip? I've no idea what it is for, but yes it does look to be a possible culprit.

have you checked under the expansion tank as well? last year I had the same amount of water loss and in my case it was the cap (changed it to a genuine one, no water loss since).

Brown clip is the temp sensor. Jack up vehicle a bit at front passengers side and pull coolant out of header tank to save loss. Undo clip and pull hose off that elbow on the head and catch the coolant. When it stops, undo the elbow from the head, remove temp sensor loom and re face the mating surface of the elbow itself. Or fit a new one. Undo temp sensor from elbow and re seat with loctite. When you refit the elbow use high temp rtv on the mating surface.
I re surfaced mine on a piece of machined resin worktop (kitchen offcut) with ally oxide paper and WD40. Be gentle and keep it flat. Dont go mad it just needs to be clean. You must have a perfect flat surface. Clean surface at the head with a razor blade.
I didnt use a gasket, just rtv. No leaks. Good luck

Now, I made some progress with this before reading the last two posts, and this is interesting.
I found that there was a leak from where the top hose is clipped on to the engine head (as per my image 1). I took the hose off here without draining any coolant (so quite a lot came out), and I replaced the pre-existing steel clip (I don't know what you call that type in the picture - where you have to squeeze them with pliers to get them off) with a jubilee clip. Before putting it back I cleaned the mating faces on the inside of the hose and on the metal male section coming out of the engine. On the metal male section there was residue of what appeared to be decayed gasket. I was surprised to find this there. I scraped all this off and cleaned the surface with a scraper and some wire wool.
Ronsealdeath - I don't know what you mean by 'elbow'. Do you mean the male section on which the hose is attached needs RTV high temp gasket, and is this why I found residue of old gasket? Or do you mean the triangular metal component that has the top hose connector) needs high temp gasket sealant when bolting it to the engine? This seems more likely.
Anyway, without high temp gasket, the leak is cured, for now. Fingers crossed.
I came on here to ask about the coolant reservoir and removing air leaks from the system. The Haynes manual says that this is achieved by lifting out the coolant reservoir by 20cm until coolant comes out of the bleed screw hole in the top hose. It doesn't explain how to take off the coolant reservoir. Is it screwed in or just held in place? There were a lot of wires packed around it so I didn't want to start tugging it about. Can someone please tell me how to take the coolant reservoir out? I tried to bleed air from the system by blowing into the coolant reservoir with the bleed hole open, but this didn't work.

Glad you made progress. Is the hose in good condition? Could the 'decaying gasket' be rust and dried coolant?

5. Remove bleed screw from top hose.
6. Unclip the bleed hose from the battery box.
7. Unclip the expansion tank from its mounting
bracket, remove the expansion tank cap and
raise the expansion tank vertically 10 cm (4 in).
Retain the tank in this position.
8. Slowly fill the system through the coolant
expansion tank until a steady flow of coolant is
emitted from the bleed hole.
9. Fit the bleed screw, then, with the expansion
tank still raised, continue filling the system until
coolant level reaches the cold level mark on
expansion tank.
10. Fit expansion tank filler cap, fit the expansion
tank to its mounting bracket and clip the bleed
hose to the battery box.
11. Start and run engine until normal operating
temperature is reached, and check for leaks.
12. Switch off engine and allow to cool.
13. Check for leaks and top-up coolant to the cold
level mark on expansion tank

Extract from RAVE -the LR workshop manual. Do a search for it and download it. It will answer most of your questions.
Griff

ANR said:

Can someone please tell me how to take the coolant reservoir out?

Click to expand...

there is no screw holding it in place only clipped on one side (see photo pos 1) and slided in a hole on the side of battery (number 2). So first gently pull the back side where number 1 clips are located then slide it out backwards from the square hole where the number 2 piece located. Then you can carefully lift and tide it to something while you do the bleed. Be careful with the small diam rigid hose connected to the top of the reservoir. Can brake easily.

Beside the bleeding procedure shown in RAVE see this too: https://www.landyzone.co.uk/land-ro...n-and-heater-not-working.365241/#post-5008999

Love this really useful thread.
Might even make me be bovvad to look for a tiny leak on mine!

Excellent, thank you all!
'Kermitrr': the hose was in good condition and there was no rust. What I called 'decayed gasket' was brown and fibrous mat about 1-2mm thick. Odd, I thought.
I'll have a go at raising the coolant reservoir and bleeding the system.
Andrew

When back up and running, get it good and hot and see how hard the top hose feels.

Thanks to all. I got the coolant reservoir out, no trouble (thought that 'swan neck' U-bend hose underneath underneath had me thinking that it was connected).
I have two questions:
1. If the hose feels soft, particularly under high temperature, is it a good idea to replace it?
2. While I had my tools out I starting looking about how to flush the radiator - just to explore the car a bit. I couldn't see the bottom hose entry point. Is the only way to access this by either taking off the front bumper or by loosening the anti-roll bar so that the plastic radiator protector/shield can be slid out?
Andrew

ANR said:

Thanks to all. I got the coolant reservoir out, no trouble (thought that 'swan neck' U-bend hose underneath underneath had me thinking that it was connected).
I have two questions:
1. If the hose feels soft, particularly under high temperature, is it a good idea to replace it?
2. While I had my tools out I starting looking about how to flush the radiator - just to explore the car a bit. I couldn't see the bottom hose entry point. Is the only way to access this by either taking off the front bumper or by loosening the anti-roll bar so that the plastic radiator protector/shield can be slid out?
Andrew

Click to expand...

1, the hose should be soft. If hard than you have a problem (if I know well).
2, if you want to remove the radiator remove the intercooler and the viscous fan first, then you will have access to top and bottom hoses. Drain the system first.
You do not need to remove bumper or anti roll bar. The plastic radiator protector shield is hold by only 2 screws from the top. After it can be pulled out.
Do you have access to Rave or other maintenance manual? Well explained and easy to do.

The definition of soft/hard is perspective. I've pressure tested and at 5psi the hose is quite firm to my fingers

Thanks,
Someone on here sent me a link to the Rave manual. I uploaded a zipped folder. When I unzipped the folder most of the files on pdf were not recognized by my computer and it would not open them.

ANR said:

Thanks,
Someone on here sent me a link to the Rave manual. I uploaded a zipped folder. When I unzipped the folder most of the files on pdf were not recognized by my computer and it would not open them.

Click to expand...

You need to replace the compatibility for WIN98. Then RAVE works.

There should be a rave icon to click on which opens it with the correct version of scrobatt