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MG Midget and Sprite Technical - Freeze Plug Leak - 1500

I started up my 76 midget that has a rebuilt engine in it that was rebuilt 10 years ago but I was the first to get it going after sitting all that time. All seems to be well (now that I got my carb issue solved).....except for the slight leak I have in the freeze plug just to the left of the distributor. It only leaks when the engine is running and the cooling system is pressurized. Is there some "quick fix" to the leak or do I just order another freeze plug and then remove and replace. ( I live in South Florida so there is no chance that the leak was caused by freezing). Thanks ..............AL
AL MILLER

I'd replace it, any quick fix is purely a get you home bodge, not a permanent repair,
Graham.
Graham P 1330 Frogeye

Al. Maybe when it was rebuilt the freeze plugs or core plugs as we call them on this side of the pond weren't replaced. As Graham says you'll have to replace it. I've just done all mine including the one in the back of the block.(my engine is out at the moment. A series.) It's not too difficult and the you'll have peace of mind instead of worrying that a quick fix is going to last.
BTW. It will have failed due to corrosion from the inside.

Bernie.
b higginson

Yeah, I guess I knew all along that I would have to replace it, but guess I had to hear it from others. I can see that all the plugs were replaced when the engine was rebuilt, so hopefully this is the only leaker. I will pry it out and see if I can get one locally rather that order it. I would "think" that a certain size core plug will fit many different engines. Thanks again ........AL
AL MILLER

Most independent auto parts stores will have those frezze plugs

I always prime and paint mine, after my truck sprang aleak due to dirt and corriosion years ago....use some really harsh paint like farm empliment or por 15, or hammerite
Prop

I never paint core plugs it's a false economy.

People will tell you that painting them will seal them. In my experience this is NEVER the case. Furthermore by NOT painting them it makes spotting any leaks/weapage far easier to spot and catch early.

Before replacing the core plug(s) get some coarse emery paper and run it around the orifice to remove any oxidation or scale build up. I then coat the sealing face of the plug(s) with a water resistant colloidal non-setting sealant such as Red Hermatite.
Deborah Evans

as ICI Paints ceased to exist around 2 years ago it appears that Hermetite is no longer made; have you found a suitable alternative?
David (davidDOTsmithAT stonesDOTcom)

A replacement for Red Hermatite is produced by the makers of Hylomar (marketed via the Hammerite people).

It is called Red Hylotite and is effectively the same stuff.

I use it for core plugs as well as for Wills Rings.


http://www.hylomar.co.uk/index.php?option=com_content&view=article&id=60:hylotyte-red&catid=1:latest-news&Itemid=18
Deborah Evans

...On my core plugs they are made from mild steel unprotected, so rust is a problem that I have a fear of. Same as on the midget

Granted there was only one time I lost a plug due to a pin hole caused from rust, and a self taper screw into the pin hole solved the imediiate issue for a couple of weeks, till a proper fix.

But for 25 cents worth of paint and 5 minutes with a brush, It sure cant hurt, I doulbt its doing any harm.

Sorry Deb, Just my personal opinion

Prop
Prop

Hopefully, you have enough room in the engine compartment to remove the old plug and seat the new one. If not, you can find freeze/core plugs with rubber and a nut that you tighten to expand to make the seal. Not as good as an all metal one, but works just fine.
Lee Fox

Thanks for all your input. I will see if I can get a core plug locally. Hopefully my car will not evolve into a "Green Hole Midget" :) ......AL
AL MILLER

Hey Al,

All the above advice is very sound and is easy to follow if the engine is out, however, I suspect you want to do what I did and replace the plug in situ, then its a different kettle of fish. I think the core plug you'll obtain will be a dome-shaped disc which needs really hammering in to seal it properly and this is very difficult to do with the engine in place. In my experience, you have to hit it hard enough to distort the crown of the dome which forces the circumference to expand and grip in the recess of the hole. After several failures I finally succeeded by using a long(about 3 feet)cold chisel/ wrecking bar (see photo) Note that the technique is to put the striking end of the bar against the plug and hammer the chisel end otherwise if you use it in the conventional manner, the "sharp" end just cuts into the disc and it doesn't expand and grip. You'll also have to remove the oil filter/engine feed line which is in the way.


M J Chapman

RE: the last post; Al's got a 1500, so the procedure would be different due to plug locations. Wish I could offer a similar suggestion, but I haven't yet had any issues with core plugs on my 1500. (I know I'll regret saying that...)

Cheers,

-:G:-
Gryf Ketcherside

Or since you said it is on the side why not just put in a block heater. That is the simple fix.
Kelvin Hawkins

The core plug that was leaking is the one just to the left of the distributor. Problem was getting it out. I removed the distributor to give me more "hammer clearance" and I was able to punch a slit in it with a sharp chisel. I then tried to pry it out using various means to no avail. Finally I screwed and forced a 1/2 inch x 2 inch lag bolt (don't know what they call them across the pond)in my plug and then using a 10 foot crow bar I was able to "easily extract" it. Found a new one at Advance auto (for 0.78 that I am still high over. Wacked it in and all is well now with no leaks.
AL MILLER

This thread was discussed between 05/12/2009 and 08/12/2009

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