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frost plug
Posted: Tue Dec 28, 2010 3:18 pm
by gerard.mcgivern
Despite being garaged,my '69 convertible has fallen victim to severe frost,with the radiator frozen solid.
I have applied mild heat and drained the radiator.Can anyone advise where the frost plug is located and what precautions should I take before trying to start up again.Cheers
Re: frost plug
Posted: Tue Dec 28, 2010 3:30 pm
by aupickup
did you not check the antifreeze level
core plugs are situated on the block on the dizzy side and one at the back of the block
wait for the ice to defrost but check that the block hasnt cracked
Re: frost plug
Posted: Tue Dec 28, 2010 5:11 pm
by rayofleamington
in Warwickshire we had -12°C last week so unless it was a heated garage, a strong dose of antifreeze is/was essential.
There are not 'frost plugs' but the cylinder block core plugs can be damaged by the frost - there are 3 round plugs on one side of the block - if any of them show any signs of movement then it's likely they will leak and the damaged ones need replacing.
As well as cracked block you may have cracked the head, and the radiator may also leak now.
Hopefully you've been lucky!
Re: frost plug
Posted: Tue Dec 28, 2010 7:50 pm
by bmcecosse
Check the water pump is free to turn.......... If so -start up and let it run at a fast idle for a max of two minutes - then switch off and check for leaks........
Re: frost plug
Posted: Sat Jan 01, 2011 4:50 pm
by gerard.mcgivern
Thanks for comments,tips and positive criticism.
I have drained and refilled,this time,with antifreeze and no leaks apparent for the moment at least...
Re: frost plug
Posted: Tue Jan 04, 2011 5:59 pm
by rayofleamington
Thanks for comments,tips and positive criticism.
I'm glad you took it as positive!

Over the years I've learnt the hard way about forgetting the antifreeze!
On one minor the pump blades were damaged by starting the engine when frozen -everything seemed normal but the heater wouldn't get warn despite the engine getting hot. After much investigation it turned out the pump didn't have any blades left and therefore couldn't push water round the heater circuit - with high revs it could push water about 2" up a heater hose (with a short hose on it open at the end to see if there was any flow) whereas with a new pump it pumped a large volume through.
Re: frost plug
Posted: Tue Jan 04, 2011 6:25 pm
by faversham999
Is the engine block ok
Re: frost plug
Posted: Thu Jan 06, 2011 8:37 pm
by gerard.mcgivern
I cannot see any evidence of cracks on the block and there is no water loss.
Also the heater is working fine,so hopefully all is well.
I do keep checking though....
Re: frost plug
Posted: Thu Jan 06, 2011 10:57 pm
by bmcecosse
And do add anti-freeze ! This winter has a long way to go yet...........despite Global Warming...........