disco core plug removal help needed!

hi guys,
i wonder if you can help me please. i need to know how to remove and re-fit the rear core plug on the cylinder head on an N reg land rover disco 2.5 diesel. as in..... do i need to take the head off it or can it be done with the head intact. is it possible to do this just by tilting the engine forward slightly?
cheers gregor

smoorach said:

hi guys,
i wonder if you can help me please. i need to know how to remove and re-fit the rear core plug on the cylinder head on an N reg land rover disco 2.5 diesel. as in..... do i need to take the head off it or can it be done with the head intact. is it possible to do this just by tilting the engine forward slightly?
cheers gregor

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If you intend to re-fit the rear core plug, I bet lots of us are wondering WHY you want to do this!

First, it is nigh impossible to remove a core plug intact. Therefore the standard removal technique is a two-stage operation:

1: buy a new plug and make sure it is exactly the right size BEFORE doing stage two.
2: belt a screwdriver through the old plug with a decent hammer, and lever the plug out.

Re-fitting is easy, but there's a neat trick to make sure it seals. Clean all around the Welch-plug recess, and get it DRY. Apply a nice layer of household gloss paint all round the recess with a small stiff brush, and rub it well in. Clean and dry the edges of the new Welch Plug, fit it into the hole and hit it as required to "pop" it so it sticks in place. Job done.

CharlesY

By the way,

I don't think you'll find it easy to do this job with the cylinder head in situ.
There just isn't enough space to work there, and you really REALLY want this job done right, don't you?

CharlesY

sorry for sounding such a twit but am typing this for my hubby so thats why i sound as if i dont know what im doing. he is good with engines and i can type fast...... thanks for the reply and yes he does want to do the job right. sorry about the re-fitting misunderstanding. what i should have said was the original plug is leaking and he is replacing it. just wanted to know if it could be done with head in situ or if it was a dismantling job really. cheers . julie

smoorach said:

sorry for sounding such a twit but am typing this for my hubby so thats why i sound as if i dont know what im doing. he is good with engines and i can type fast...... thanks for the reply and yes he does want to do the job right. sorry about the re-fitting misunderstanding. what i should have said was the original plug is leaking and he is replacing it. just wanted to know if it could be done with head in situ or if it was a dismantling job really. cheers . julie

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OK Dokay ......

Well, that was a sure bet!
Always the ONE that is so hard to get at which leaks.

You could spend ages playing smart trying to extract the old plug with the engine and head in place but ..... nonetheless, I bet someone has done it!
.

And another thing, if only you (I mean your hubby .... ) could get at the plug, a permanent fix can often be achieved using a pan-headed self tapping screw with a neat-fitting copper washer under its head. You just drive it into the Welch plug right through the leaking pinhole.

There is so much work to do to move the engine any way you try, it really boils down to taking the cylinder head off, or moving the whole engine off the gearbox (fit a new clutch at the same time?), in both cases so that there is enough space behind the head to work on that core plug.

What a bummer.

CharlesY

Charles,
thanks so much for your help its much appreciated. hubby now heading out to get down and dirty removing the head... While grumbling!!!.
Bloody disco is nothing but trouble think ill stick with the rangy it seems to be more reliable..... (touching everything wooden in sight). Julie

Another little tip that can be used on core plugs, which I have done 100's of times is to freeze the new core plug prior to fitting. This has the effect of slightly shrinking it which makes it ever so easy to fit. Desired coldness can be achieved by putting it in the freezer or using a great product call 'wurth Rost off ice'

I tried the freezing method a couple of times, but invariably condensation forms on the cold disk, which means my gloss paint doesn't stick to it as well.

The plugs are dished outwards (fit them dished side OUT) and because of that they are a tiny bit smaller in diameter than when they are flat, or flatter. So, they slip into the hole neatly (if they are the right size!) and then when you whump them in the middle to flatten them a bit they pop in a bit like a diaphragm and get BIGGER IN DIAMETER, and they get a mighty grip.

The best way to insert a Welch plug is to use a socket that JUST fits the hole for the plug. This will drive the plug disk into the hole by its outer edge only, and it will slip in easily. Then you whump it in the middle to flatten it.

That was Mr Welch's invention, a long long time ago ....

CharlesY