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MG MGA - Radiator Leaks when cold

When my mechanic last worked on my 58A,1500, he told me my radiator had a small leak--when cold...but was okay when hot???
In fact, I only experience a small loss, and it's usually on the garage floor after a drive.
How hard is it to remove the radiator. My car is pristine after a full nut & bolt, body off restoration and repaint...it's better than new-except that radiator leak. I'm almost afraid to work on it for fear of scratching her.
Any hints and/or advice on removing the radiator?
Joe Walck

Do a cooling system pressure test when it is cold. See here:
http://mgaguru.com/mgtech/tools/ts128.htm
http://mgaguru.com/mgtech/cooling/cool_106.htm

If you don't have the tester and don't want to buy one, any radiator shop can pressure test it for you. Many auto parts stores may also test it for you. East yo fond any leak this way,l and you can see where it leaks (unless it is a head gasket looking coolant into the engine). If it doesn't leak under pressure when cold, your mechanic is mistaken.
Barney Gaylord

The next morning, after a drive, I have about 2 oz. of my green/yellow antifreeze on the garage floor, under the radiator. It's definitely coming from the lower 1/4 of the radiator.
Joe Walck

Joe,

I had a leak in an engine block forty odd years ago; the engine was a cross flow type where there was a steel tube pressed in the block running from one side of the block to the other. The tube carried exhaust gas indirectly through the block to heat up the carburettor. Anyway the tube developed a leak which was initially small and manageable but after a while the drip increased into a trickle.

At the time I didn't fancy pulling the engine and sending it off for repair and someone recommended I try putting something called 'Bar's leaks' in the radiator. I was very,very sceptical of this idea as I don't normally go for 'bodge' jobs but I decided to give it a go. As far as I remember the procedure was to get the engine and coolant warm and just add the whole bottle (less than a 1/4 pint). This I did and I was amazed at the result; the leak went from a continuous trickle to zero in one to two minutes. It was so successful that I resumed running the car and continued for a couple of years (until I changed it) with no sign of the leak reappearing and no apparent after effects of the treatment.
I've just noticed on the internet that 'Bar's leaks' is still being made which is not bad after 45 years. Anything that survives that long can't be all that bad.

See:- http://www.barsleaks.net/how2works.html

Apparently it doesn't create any coagulant in the cooling system and if it doesn't work you can always drain the system and you've only lost the cost of it plus a bit of antifreeze.

If instead you decide to remove the radiator I would suggest you get a second pair of hands to help you lift it out because I found it is a fairly close fit................................Mike
m.j. moore

Are you sure that it's not just coming from the overflow pipe. Coolant will expand when hot (and get hotter when the engine is switched off) & will drop coolant on the floor as it expands. Common thing. The fix is a coolant overflow recovery tank.
Do you have a 7lb radiator cap?
I B Morris

It might be, I just noticed the overflow only extends 1/2 down the side of the radiator. I added a piece of hose/tubing, and will test when it stops raining.
Joe Walck

Joe,
It might be that the leak is soo small that when the car is running the heat from the rad and the air flow from the fan and car movement make the coolant evaporate, and you don't see any leak,,,, once the car stops, the rad cools, and the air flow stops,, and ,,,, you see the small leak that is always there,,,,

SPW
STEVE WINCZE

This thread was discussed between 17/05/2013 and 22/05/2013

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