Coolant leak from rear of cylinder head.

My 300tdi seems to have sprung a coolant leek at the back of the engine, on the cylinder head block. Looks like the core plug as failed. See image below



What's the best way to tackle this? Engine out or take the head off?

Yup. Hole in the core plug. Little hole at 11 o'clock to the bead of water.

Benny_Boy said:

Yup. Hole in the core plug. Little hole at 11 o'clock to the bead of water.

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Clean it out, fill the core pug with JB weld until you need to take the engine out or head off for another reason, been there done this.

JB Weld HighHeat 57g Heat Temperature Resistant Epoxy Putty Metal Repair Filler 43425082978 | eBay

How much gap between back of head and bulkhead?

K seal is very good.

lynall said:

K seal is pish.

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Corrected that for you.

lynall said:

How much gap between back of head and bulkhead?

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About 25cm straight back from the failed plug.

I've read of others using epoxy, but yet others saying it should only be considered a 'get you home' repair. Thoughts?

25 CMS?
Could do that in situ I would have thought.
Have you done one before?

Flossie said:

25 CMS?
Could do that in situ I would have thought.
Have you done one before?

Click to expand...

Nope. Never. Only just found out what those recesses were after that little fountain appeared.

From what I've read the technique is:

1. Drain coolant.
2. Stab a screwdriver through the middle and prise the cap out.
3. Clean up mating face in the block with emery.
4. Hylomar the mating faces
5. Insert new plug using (ideally) a socket the same diameter as the plug's OD and tap gently home.

Sounds ok? Any tips or other instructions?

Benny_Boy said:

Nope. Never. Only just found out what those recesses were after that little fountain appeared.

From what I've read the technique is:

1. Drain coolant.
2. Stab a screwdriver through the middle and prise the cap out.
3. Clean up mating face in the block with emery.
4. Hylomar the mating faces
5. Insert new plug using (ideally) a socket the same diameter as the plug's OD and tap gently home.

Sounds ok? Any tips or other instructions?

Click to expand...

Nope, that's it.

Just like that...

As said 25cm clearance I would do that in situ, I have an old shaping chisel that I drive into the side of the core plug then use it as a lever to pop the plug out, some people use self tappers then lever the plug out, others drive them inwards then turn them sideways to extract them.
Bet there are some vids on youtube?

Red hylomar is best.

Flossie said:

Red hylomar is best.

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Got blue. Is that ok?

No.
Red.