Manky Monkey Motors

Leaking cylinder head core plug ?

The core plugs are 1 and a 1/2 inch in diameter .
The Reliant part number for the core plug is 10072

As the coreplugs are so cheap , it would make sense to buy 2 or 3 in the event that if one is damaged during fitting you can then use the other spare one.

The core plugs are dished and are fitted with the dish pointing outwards .

The core plug is then gently thumped in the middle of the dish with the ball end of a ball-pein hammer by striking the flat end of the ball-pein with a mallet .

The secret is only to strike the core plug till it is flat .
As the core plug flattens it spreads out and seals the side .

However , if you are too heavy with the hammer you will cause the core plug to dish inwards and therefore draw the plug away from the sides again !

If it is only a slight weap at the side of the core plug , and the plug is not fully flattened or dished inwards , then you might get away with not removing the core plug by just giving it a tiny bit more dunt as above .

If that does not work then you will need to fit a new plug

REMOVAL; {Unless your engine has already spat the core plug out ! }

Drain the coolant from the block via the wee drain plug on the exhaust side of the block at the rear just below the head and in front of the gearbox .

Choices as to removal ;

{ 1 } Get a dollop of grease and bung it on the core plug to catch the drill swarf .
Drill a hole in the core plug to suit a large self tapper screw .
Screw the self tapper into the core plug leaving a good portion out
Hold the screw with pliers and hit the pliers with a hammer.

{ 2 } Get a dollop of grease and bung it on the core plug to catch the drill swarf  .
Drill a hole in the core plug
Gently bash a screwdriver through the hole in the centre of the core plug and prise the plug out using a wee block of wood under the screwdriver to avoid damaging the head .
Do not go too far into the core plug or the end of the screwdriver will catch on the inside of the head as you try to prise it off

{ 3 } Use a very small sharp chisel to make the hole in the core plug and then use either screw or screwdriver methods { 1 } or { 2 } above

FITTING

Thoroughly and gently clean the recess in the head where the core plug butts against .

The core plugs are dished and are fitted with the dish pointing outwards .

The core plug is then inserted into the cylinder head * and gently thumped in the middle of the dish with the ball end of a ball-pein hammer by striking the flat end of the ball-pein with a mallet .

The secret is only to strike the core plug till it is flat .

As the core plug flattens it spreads out and seals the side .

However , if you are too heavy with the hammer you will cause the core plug to dish inwards and therefore draw the plug away from the sides again !

*I have only ever put them in bare** but some folk put a smear of  sealer { blue gasket sealer or similar } around the lip where it seals .
Either way should work .
.
**I mean the core plug is bare , not me  ;D ;D


 

As always, useful & concise info Mr F.
I'm no master mechanic, but it's easy to forget a lot of people have no experience of working with engines at all. Today's teenagers are very limited in what they can do on their cars, even if they wanted to, by the technology involved in them. This is the kind of thing us oldies would've picked up from our Dads or mates or whatever but nobody gets taught these days.
More please!

very useful info, just done mine using that info, not sure i have hit it hard
 enough cos is still very bowed out, will find out when i get it filled back up.

I had one blow out on my first Reliant trike. One minute I was sat in traffic, waiting to pull out onto a roundabout, the next I was enveloped in a cloud of steam & couldn't see where I was going!

oops, think i will give it a couple more hits just to make sure, bet that warmed up your bits :o

Funny, I helped my OH rebuild engines (mostly 100e, 113e and the like) for severl years in our rallying days, but I'd never even heard of a core plug until two of them starting leaking on my VW Passat!

ive just removed the one at the back of the head(cos it was weeping,well,crying actually  ;D) Christ,it was hard to gaet out! I really had to give it large with a big hammer!

mine just fell out cos it was as thin as a fag paper.

Rod , did you say " Core , this is hard to get out "  ;D ;D
.
.

Well yes, I did ,but it was in another language,went summat like "This f******,b******,****,wont move"

Had to replace them on a 4.2 straight six Jag. (think there were three) Cost about a quid each but the dealer wanted over £400 to do the work and that was twenty tears ago.
A real sod to get to, all the induction and exhaust had to be removed first. The block was full of gunk, so it gave me a chance to hose it all out. If I rebuild an engine, I replace all the plugs if there is any doubt about them.

Good idea. I completely forgot bout mine when I rebuilt it!