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 - Core Plugs

Well it's the cold has settled in so I have decided to address some of the little issues I developed over the summer. I had a "Core Plug" fail on the side of the engine. It appears to have just popped out slightly draining all my coolant. Well I stuck it back in and tapped it a few times. It's held since but still makes me nervous. I can see coolant slightly leaking around it. I am sure they were installed incorrectly as mentioned in Barney’s site. I also ordered the "Screw down type" as a backup just in case. Is there a good technique to get a good whack on the existing plug? Can I assume it’s holding since it’s lasted several months of hot weather driving? Should natural corrosion seal up the little bit of leaking? Or should I break down and just put the "Screw type" that I purchased for my backup and be done with it?
Thanks!
WMR Bill

Bill,
FWIW, I had a slow coolant leak on my Jag, lasted for two years, before I traced it to a core plug. The plugs were all replaced when the engine was rebuilt some years previously. I couldn't find it until I got a pressure tester. I sealed it initially with Radweld, but it came back. No choice but to change the plug.

Neil
Neil McGurk

The natural corrosion won't seal the leak, in fact it could etch the area and cause a new plug not to seal properly. I'm not a fan of the "screw type" plugs except as an emergency measure. I'd advise that you just pop the old plug out, clean up the hole well and install another plug. A correctly installed brass plug shouldn't need any additional sealer to work, the brass should be soft enough to conform to the iron of the block.
Bill Young

The new plugs I received from Moss do not appear to be brass, should they be? Also, any suggestions how to whack it while the engine is in? there just does not seem to be that much room!
WMR Bill

No, they are not brass, but a soft steel. And yes it is hard to put them in with the engine is in place. I replaced the rear one once by removing the bulkhead plate over the gearbox, but it would have been quicker to hook the engine out and do it. If it's a side one, you may just manage it by removing all the bts that are in the way.

dominic clancy

Core plugs are pretty generic, go by cup or disc type and size. You should be able to buy replacements in either brass or steel at your local auto parts store.
Bill Young

Anyone use these:

http://cgi.ebay.com/ebaymotors/MG-MGA-MGB-GT-EXPANDING-COPPER-ENGINE-FREEZE-PLUG-SET_W0QQcmdZViewItemQQcategoryZ33613QQihZ005QQitemZ150197815895QQrdZ1QQsspagenameZWD1VQQtrksidZp1638Q2em118Q2el1247

Comments (other than pricey)?

Steve
Steve Brandt

Bill. The B series engine uses a disc type plug which fits into a counterbore in the engine block. I agree that this is a job best done with the engine out of the car.

Remove the old plugs and use a small cup type wire brush to clean, throughly, the recess. Clean the recess with a good solvent to remove any oil, coolant, or rust which has been loosened by the wire brush. Clean the new core plugs with a good solvent. Put a small bead of J-B Weld into the corner of the counterbore, insert the new core plug, and flatten the center, expanding it into the counterbore, using a piece of 1" round steel rod.

Steve. This type of plug is available at many auto parts stores at about $2 each. Good thing to have in the car's tool box in case a plug pops out when traveling. It sticks out farther than the factory plugs and does not do any better job of sealing than a factory plug installed as I have described. The B series engine uses a 1 5/8" plug, a common size.

Les
Les Bengtson

Have you noticed that the dished plugs tend to have two little opposing lumps on the edge, as if the stamping was made with two semicircular cutters and then parted?

At least, that's what mine were like, and the first one I hammered in - before I noticed - wept copiously.
Nick

Steve, I use them on occasion. See here: http://www.mgnuts.com/tidbits/tempfreezeplug/
Steve Simmons

Steve. I have not. The plugs I use are all old "Rover" brand and do not demonstrate this characteristic. I just went out and examined the three Rover core plugs in my spare parts locker and all of them are the same around the edges. What brand of core plugs did you have problems with?

Les
Les Bengtson

Steve - I bought a box of 5 ( minimum quantity) of the screw type ones - a lot cheaper than the $24 on ebay - I got them from Rockauto by mail order - keep them as an emergency but not used them yet.
Cam Cunningham

I have a factory Gold Seal Sherpa 1622 engine. This has cup core plugs in. Not seen this before on a B series.
Being a Ford man, I think these cup plugs are better than the MG type.

But what do I know???

Colin
Colin Parkinson

This thread was discussed between 11/02/2008 and 12/02/2008

MG MGA index

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