cylinder head coreplug

There is water weeping from a couple of tiny holes in a small coreplug on the top of the cylinder head between the second and third cylinder head studs.How do I repair this? I have replaced the large coreplugs on the outside of the engine block before, but this is a new one to me.  Andrew Posted by tf1695 09/04/2013 15:05:59

I would take the cylinder head off and do all of them.... If one is leaking, they are all probably equally corroded. While the head is off, pull the block off and do them too! Posted by IanHardaker 09/04/2013 19:15:42

Andrew They are aluminium plugs and  are screwed in,if one has gone there are 3 more to worry about on TA/TC.(8 on TD/E ) I believe you have to drill them out and clean up the thread ,screw in the new one and cut it of flush with the top surface. The part no. is N5631 and they used to cost 1s5d!. They are totally different from the external welch washers on the side of the block. Posted by Peter Martin 09/04/2013 20:21:02

Thankyou for your help Ian and Peter,       I've got the coreplugs from RT, I am going to remove one from a spare cylinder head and see how that goes before I make a mess and put the car off the road !   Andrew Posted by tf1695 14/04/2013 12:01:09

Andrew  Please let us know how you get on as there are a lot of 3 litres out there probabley   heading for this problem.  Ian , I think & hope it is only an issue for the head on post war 6's but may be wrong (The block and crankcase are not seperate)  Peter Posted by Peter Martin 14/04/2013 15:00:04

Hi Peter, I didn't notice that this was on a 3 litre forum... I saw the tf16.95 name and thought it was a pre-war car! Posted by IanHardaker 14/04/2013 21:52:19

Hello Andrew, Thanks for posting your question about the problem you are having with a weak head core plug.  We should all watch and be prepared to replace these plugs due to age and less than perfect water in our radiator systems.   Also, you mentioned that you have a spare head?  What model is it from?  I am looking for a later series Alvis head to trans-plant on my TA-21 project. Regards, Alan Posted by alsfarms 03/05/2013 14:13:55