MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - Rear Core Plug

I noticed over the weekend that I have a weep from the rear core plug on my 1600 Mk 1 Coupe and I would like to sort it out before the fine weather arrives [which probably gives me several months yet!].

How have others carried out the necessary replacement in this very tight location? Is it automatically an engine out requirement or are there other ways of tackling it.

I seem to remember some years ago a thread about alternative types of core plug but I cannot find it in the archives - can an alternative type be fitted without taking the engine out?.

Any help would be appreciated.

Maurice.
M. Standish

Maurice

My ten pennyworth is that it's an engine out job. I cannot see how you can get the leverage to get the old one out nor have the space to hammer the new one in.

Steve
Steve Gyles

I have re-seated one by putting a piece of wood along the firewall as a load spreader and using a nut and bolt as a jack to press it back in. If you get the bolt head in the centre of the core plug it will push in the dome and improve the seal.

If the leak is because the plug is corroded then a new one is needed and the above technique might work but getting the old one out could be tricky.

Malcolm
Malcolm Asquith

Malcolm

I like your idea for pressing it in. Fingers crossed the firewall takes the spread pressure. Stored that in my little grey cells for future use. As we both say, getting one out from there would be tricky.

I replaced mine and did a water gallery clean out when I took my engine out for its cosmetic overhaul 3 months ago. I was praying that the rear one was sealed up ok as I did not want to go for my 7th engine out in 10 years.

Steve
Steve Gyles

Hi Maurice, As already said by Steve and Malcolm it is usually an engine out job. If you can get the plug out I have a spare Dorman core plug that is put in the hole and then tightened with a spanner . It is a get you home type plug if one blows out - bought a pack of 5 from Rockauto in USA last year - £6 post paid if you want one - cheers Cam


Cam Cunningham

Cam,

That obviously the type I had in mind when I was thinking about alternative types of plug, but I didn't appreciate that they weren't permanent. It's kind of you to offer me one and I'll take you up on that if you don't mind. Please e-mail me to make arrangements.

I like the sound of Malcolm's suggestion and I'll probably try that method before going the engine out route.

Has anyone used any sort of sealant when replacing core plugs? - its a long time since I did one and I've only ever put them in 'dry', but I wonder with modern materials if it's now usual to use some sort of sealant.

Thanks for all your comments.

Maurice.
M. Standish

It is possible to push the rear core plug out as follows:

Drain the coolant.
Remove or water proof the distributor.
Remove the core plug over the distributor.
Insert a long thin screwdriver between the edge of the core plug and rear cylinder jacket to hammer (gently) the rear core plug out.
Clean the seat for both plugs well, use the Dorman plug or the nut and bolt method mentioned above to insert the new rear and plug replace the plug over the distributor.
Russ
Russ Carnes

Cam and MS - Have a look in Barney's site where he describes it as a permanent installation. Seems pretty solid to me the way Barney describes it.
J H Cole

Russ & J.H.,

Excellent suggestions both. I should have thought about looking at Barney's site but didn't - I'll learn eventually. As J.H. says it sound as though a Dorman plug could be permanent and it would be interesting to hear Barney's opinion on this.

I'm in the office at the moment so cannot look at the engine, but Russ's method for removing the old plug sounds like a good way to go without removing the engine, which I'd dearly like to do if possible.

Thanks again for the suggestions.

Maurice.
M. Standish

You could put a thin coat of JB weld on the core plug circumference surface that sets in the block before installing.

George
G Goeppner

I put some Wellseal non-hardening joining sealant on both mating surfaces. Not sure whether the purists will say this was necessary but I have no leaks, so I am happy.

I guess it's like keeping a light on outside the house to keep the pink elephants away. Not seen one yet, so it must work!

Steve
Steve Gyles

If you think Dorman plugs aren't permanent just try to remove one! I have an 1800 motor with a Dorman installed. Removed the nut and tried to pull it out. Didn't budge. Looks like I'll have to cut it. I love Russ's tip about getting the rear plug out. I too will file that away for future use.
Cheers,
GTF
G T Foster

Hi Maurice - I will email you later ( after England Match). The core plug is advertised as temporary but a friend of mine has one in an mgtf block that was put in over 10 years ago before the car was brought back from USA -and is still holding - looks like from GTFs comment it could be as permanent as the originals - cheers Cam
Cam Cunningham

I put the Doorman plug in my A in 1995, I used Permatex Grey to seat the metal plug, no leaks.
Russ
Russ Carnes

Since the Dorman plug is more expensive than the standard dome Welch plug, the Dorman plug is the emergency replacement plug. I wouldn't call it temporary, as it is harder to remove than the standard type plug. Same procedure for removal though, drill a hole, install a large screw, and pull.
Barney Gaylord

In my experience the new plug should always be brass.
Barry
BM Gannon

Good point, right angle drill if not too long, sawed off drill bit, lag screw, nail bar; might work!
Russ
Russ Carnes

It is possible to get at the rear plug from inside the car by removing the bulkhead panel that screws to the goalposts.

I did it once.

Next time I'll take the engine out and do it the easy way!
dominic clancy

This thread was discussed between 03/03/2010 and 04/03/2010

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.