Cooling System blocked drain tap

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Zac
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Location: Gwynedd

Cooling System blocked drain tap

Post by Zac »

Dear All,

I cannot drain the block. The drain tap opens and closes. No water comes out.
What is the best way to get the brass nut that holds the tap into the block off?
Can this be done without removing the engine from the car?
The car stood for 50 years after the system was drained. I can force air up into the tap with a foot pump.
Maybe the best thing might be to reassemble it all and run it with a compound in the hope that the heat and circulation frees it?
Amy suggestions would be helpful.
Zac.
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Zac
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Re: Cooling System blocked drain tap

Post by Zac »

The tap is of the butterfly variety and I cannot get a ring spanner over it!
Edosan
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Re: Cooling System blocked drain tap

Post by Edosan »

I would leave it until you're doing a major engine rebuild, had a few like this over the years and they mostly just block up because they are never used. I think it is a remnant from the days before Anti-Freeze when all water had to be drained out if you were leaving the engine in the cold. Just fill up with good strength anti-freeze and forget about it. :wave:
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Zac
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Location: Gwynedd

Re: Cooling System blocked drain tap

Post by Zac »

Thank you for your advice, Edosan!
I had been hoping to completely clean up the whole engine block cooling system as I was worried that any dislodged sediment particles would block up the newly cored radiator once I had reassembled the cooling system. I certainly think that you are right in saying that one of the previous owners drained the block to save it from freezing up, although there are early 60's anti freeze stickers in the windscreen.

I had the idea that I could modify a box spanner so that it would fit over the tap's wings and onto the brass nut to get the best grip and then remove the exhaust downpipe to give me more room to swing the bar. I am also considering gentle heat to that area of the block into which the brass tap screws.

I have also bought a second hand brass tap just in case I completely disfigure the original. If all the above fail then I will just refill with fresh coolant like you say and keep an eye on it.

Once the cooling system is done then I will turn my attention to the brakes.
Edosan
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Re: Cooling System blocked drain tap

Post by Edosan »

Hi Zak, if you're determined to get it out can you not put a mole wrench on the butterfly end and maybe use the heat doubt there is much sediment if you have flushed it through. :wave:
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HUX
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Re: Cooling System blocked drain tap

Post by HUX »

Hi Zak,
I had a blocked engine block drain tap and managed to clear it without removal.
With the tap in the open position I inserted a piece of coat hanger wire with the end very slightly bent, and rotated this gripping it with a mole wrench, till I got a little gunge through. I had the Cylinder head off at the time, and was able to direct the wee bent wire in through the water channels in the top of the head, and revolving it by putting it in a drill chuck, which eventually pretty much cleared the blockage.
Good luck!
All the best
Alasdair
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