Water leak from cylinder head

[PaulH]

I'm seeking some of your expert advice. I think I've spotted a small water leak from the cylinder head of my 1966 Elan S2. The image shows where I think the leak is, between exhaust manifold of cylinders 3 & 4. Is this a core plug? Any thoughts about the best approach to resolve it? Clearly I'm hoping I don't have to remove the head. It's the earlier type of cylinder head (sand cast?).

Paul

[types26/36]

Yes there are several core plugs on the S1/2 heads, two on the exhaust side, one at the rear of the head, one at the inlet side and one at the top of the head near no.1 spark plug.
You should be able to replace them in situ except for the one at the rear which needs the head off.
When I replaced the ones at the exhaust side I tapped the holes and fitted threaded plugs.
Sometimes you can get them to stop leaking by a gentle tap in the centre.

[PaulH]

Yes there are several core plugs on the S1/2 heads, two on the exhaust side, one at the rear of the head, one at the inlet side and one at the top of the head near no.1 spark plug.
You should be able to replace them in situ except for the one at the rear which needs the head off.
When I replaced the ones at the exhaust side I tapped the holes and fitted threaded plugs.
Sometimes you can get them to stop leaking by a gentle tap in the centre.

That's very helpful. Glad to know I should be able to resolve it with the head in place.
Thanks,
Paul

[gjz30075]

I second that, as I just did mine (except the rear one). I drilled a small hole in the center of the plug and
screwed in a sheet metal screw. I'm then able to grab the screw with a vice grip type of puller and yank
them out. I tapped the new ones in with a small socket, then dimpled the middle with a blunt punch.