Disco 2 Catastrophic water leak.

TD5 15P engine.

I seem to have lost something from the back of the cylinder head. There's a hole there that water runs out of when I top up the water. How bad is this situation? Can I fix it with the engine in place?

It's named "coolant jacket core plug" you should be able to fit one in situ with some contorsionism and handyness, it's about fixing it in place and tap it in nr 16 https://parts.jaguarlandroverclassic.com/parts/index/part/id/L5.L5G.L5G01.L5G01035/brand/land-rover/

That looks like a missing core plug. not sure if it can be done in situ, DO NOT DRIVE IT UNTIL FIXED.

Search up on it may be videos.

MJI said:

DO NOT DRIVE IT UNTIL FIXED.

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Too late. I already have. That's how I discovered it was missing. Thankfully not far and I don't seem to have done any damage.

sierrafery said:

It's named "coolant jacket core plug" you should be able to fit one in situ with some contorsionism and handyness, it's about fixing it in place and tap it in nr 16

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Thanks very much. I've ordered one. It's just an interference fit then?

Last time I changed one (Rootes short stroke 1600) it was fit by hitting it gently with something to keep it parallel.

I saw my mechanic doing the rear camshaft seal in situ with a slide hammer which had a long home made L shaped extension to cover the seal, maybe such thing would do the plug too if you cant use a normal hammer to tap it...eventually a hammerhead automatic tool... though i'm quite dumb when it comes to mechanical procedures and that space seems tight enough

DefenderPilot said:

TD5 15P engine.

I seem to have lost something from the back of the cylinder head. There's a hole there that water runs out of when I top up the water. How bad is this situation? Can I fix it with the engine in place?

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Leaking as a result of a lack of corrosion inhibitor (antifreeze) in the coolant.
You could try this stuff, but it may only temporarily… but I don’t expect u have a Halfords nearby in Shetland
https://www.halfords.com/motoring/e.../wynns-radiator-stop-leak---325ml-130652.html
Also to let u know what a core plug is.
https://en.m.wikipedia.org/wiki/Core_plug#:~:text=from the engine.-,Design,caused by cooling system water.
I don’t know how many core plugs your engine has, but if one starts leaking one or more will follow if your unlucky.
As I found out in my old RR days.

discool said:

Leaking as a result of a lack of corrosion inhibitor (antifreeze) in the coolant.
You could try this stuff, but it may only temporarily… but I don’t expect u have a Halfords nearby in Shetland
https://www.halfords.com/motoring/e.../wynns-radiator-stop-leak---325ml-130652.html
Also to let u know what a core plug is.
https://en.m.wikipedia.org/wiki/Core_plug#:~:text=from the engine.-,Design,caused by cooling system water.
I don’t know how many core plugs your engine has, but if one starts leaking one or more will follow if your unlucky.
As I found out in my old RR days.

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well every day is a school day as I never knew that with regards to the casting , just wished to say many thks for sharing the link

gstuart said:

well every day is a school day as I never knew that with regards to the casting , just wished to say many thks for sharing the link

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So it is
I was told way back when I moved over from motor bikes to a car and asked ‘whats that’. I was told they were to there protect the block from cracking if it froze in winter by popping out, so I must drain and fill with antifreeze when winter came, as you did before antifreeze became an all round stuff… along with oils becoming multi grade.

discool said:

So it is
I was told way back when I moved over from motor bikes to a car and asked ‘whats that’. I was told they were to there protect the block from cracking if it froze in winter by popping out, so I must drain and fill with antifreeze when winter came, as you did before antifreeze became an all round stuff… along with oils becoming multi grade.

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Looking back i still remember those horrible curved discs , where u had to place them just right in order to hit the middle forcing them to the sides , the amount of times I either hit them too hard or not enough , lol

must confess the first time I saw them I always thought they were to protect the engine if it overheated , luckily later on my pops and brothers put me straight about them , my pops was a heavy goods mechanic back in the 80’s when I first started getting into cars , still remember my mum doing her nut with us 3 x boys each having our cars in bits on the driveway , oil in the kitchen sink and on the tea towels , lol

gstuart said:

Looking back i still remember those horrible curved discs , where u had to place them just right in order to hit the middle forcing them to the sides , the amount of times I either hit them too hard or not enough ,

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Concave & Convex u decided
Four of us had part ownership of an Alvis with leaking core plugs when it was purchased, even all of us being at an engineering collage we couldn’t decide…although it is logical but it wasn’t then. lucky we could get spares at the local auto parts shop.

What with work and waiting for the part to arrive I've only just got back on to this today.

I made up a brace to place against the bulkhead which locates in the webs of the top of the bell housing. This is to place a bolt with a socket and washers to use as a press between the bulkhead and core plug to press the core plug in. It worked quite well until the point where the core plug "jumped" in a bit too far. You can't actually see what you're doing and I had to keep taking pictures with my phone to see how I was doing. You can see what I mean in the pictures below. Does the collective think this will be OK? I'm going to fill it up and go for a short drive anyway to see what happens.

There doesn't seem to be any sign of sealant on it, was there?

I'd have stopped at the point where the lip was just on the outside.

It'll prolly be OK but you have exposed more surface area to the coolant.should be OK if you put lots of anti freeze in.
It's got 2 chances!

Have to say I actually like the way you did it.
The "jump" would have been caused when the lip folded up and provided no more resistance. That is what it is there for I have to guess. To tell you where to stop!!

Well I've just come back from a test drive. No leaks but she got rather hot. Looks like the water pump was also a casualty.

I've got another engine in the corner of the garage and I used the position of the plug on that as a guide. It's about 2mm in from flush. That's what I was going for. I'm about 4 or 5 mm in. Time will tell I suppose.

Time to order a new water pump. Hope it comes a bit quicker than the core plug did. That took a week.

DefenderPilot said:

Well I've just come back from a test drive. No leaks but she got rather hot. Looks like the water pump was also a casualty.

I've got another engine in the corner of the garage and I used the position of the plug on that as a guide. It's about 2mm in from flush. That's what I was going for. I'm about 4 or 5 mm in. Time will tell I suppose.

Time to order a new water pump. Hope it comes a bit quicker than the core plug did. That took a week.

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R U Sure it's the pump?
Is it leaking out of the almost impossible to see tell tale hole on the bottom of it?
Could also be that you've cooked the thermostat, which is where I would look first.
Anyway best of luck and I can see what you mean about the fitting of the core plug. But, (dare I say this), the originals maye have had no lip. However 2mm will make feck all difference. So that job is jobbed. I did a water pump last May quite easy although time consuming and fiddly. Good time to change the centrifugal filter, main oil filter and do an oil change, if you are that way inclined. You don't have to take everything off just move a lot of it aside.
Best of luck!

DefenderPilot said:

No leaks but she got rather hot.

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You sure its fully bled of air?

J

Cheers Mr. Steamer. I'm assuming the pump impeller has been sheared off the shaft when trying to start the engine with the coolant frozen. There doesn't appear to be any return flow into the header tank with the engine running so I'm assuming the pump isn't pumping. I'm going to remove it tomorrow anyway so it should be obvious if that's the culprit.

marjon said:

You sure its fully bled of air?

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Pretty sure. I filled it until water was coming out of the bleed screw. I've done this loads of times and never had any issues with air locks. I'll be taking the pump out anyway to check it.