Small hole in engine block leaking water

Hi,

I've got a 1956, 88", Series 1.

I've just replaced my water pump (impellor bust) and when i ran the engine to test it, i noticed a small leak on the left side of the engine block, coming out of a hole approx 3mm. The water hits the alternator as it sprays out.
The hole is on a circular piece of metal (approx 5cm in diameter) which is slightly recessed. Would i be right in thinking that this is a 'safety pressure' - type thing, which is designed to break to release steam if the water pump failed as mine did?

If so is it replacable? It looks like it a big plug. Sorry for being so lame - i love the old girl - but a mechanic i'm NOT!

Any suggestions gratefully received.

Andy

It's a core plug - about 45p

Yep, sounds like you've got a coreplug gone, if they've been in for donkeys years they can rust through. It's a fairly straight forward job providing you can get to it easy.They're put in the block in case the coolant freezes,instead of the ice cracking the block it pushes the coreplug out

Cheers Mat Hat Man!

You know what i'm going to ask next... - what's the best way to remove the old knacked core plug?

Nice one V8Jon - may i put the same question (about removal of core plug) to you....

Smack a big screwdriver into it and leaver it out,may break up just make shure you remove it all.Clean up hole with emery and tap in new plug,a socket that fits inside helps.Some bearing seal on outside edge will help make it water tight.

All's good! Got the old core plug out with some leavering, more leavering and...some swearing! Wasn't getting it out which was the difficult bit - with engine in situ, replacing it was a trick! Got there in the end.
Replaced the water pump aswell (impellor had bought it) and she's back to full health. Or nearly- i noticed a small drip coming from the join between water thermo housing and wp on run test, guess the gaskets/washers must have not bedded in 100%. Thought i might try some rad weld in the rad as it's only a tiny leak.

Thanks for all your help chaps...spring on it's way!!